answer chem p score x a plus module 2013

7/21/2019 Answer Chem p Score x a Plus Module 2013

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@Hak cipta BPSBPSK/SBP/2013

1Perfect Score & X A –Plus Module/ark sc!ee 2013

BAHAGIAN PENGURUSAN

SEKOLAH BERASRAMA PENUH DAN SEKOLAH KLUSTER

JAWAPANMODUL PERFECT SCORE &

X A-PLUS

2013

CHEMISTRY

Set 1

Set 2

Set 3

Set 4

Set 5

http://cikguadura.wordpress.com/





MODULE PERFECT SCORE & X A-PLUS 2013

SET 1 :THE STRUCTURE OF ATOM, PERIODIC TABLE OF ELEMENTS AND

CHEMICAL BONDS

Ques!"# N" M$% s'(e)es M$%

1 (a) (i) Melting 1(ii) Molecule 1

(b) The heat energy absorbed by the particles is used to overcome the forces of attraction

between the naphthalene molecules / particles.

1

(c) The particles move faster 1

(d) (i) X : electron : nucleus 1

(ii) !lectron 1

(e) (i) " and X 1(ii) " and X atom have different number of neutrons but same number of protons

#tom// !lement " and X has different nucleon number but same proton number

1$1

%

&uestion 'o Mar schemes Mar

(a) 'o of electrons * 1+, 'o of neutrons * 1$1

(b) (i) The total number of protons and neutrons in the nucleus of an atom 1

(ii) -

(c) (i) .1 1

(ii)

X

(d) (i) " and 1

(ii) #tom " and have the same number of valence electrons 1

(iii) To estimate the age of fossils /artefacts. 1

%

X

X

e

3*

+#X e

e

X






Ques!"# N" M$% S'(e)e M$%s

3 (a) (i) Total number of protons and neutrons in the nucleus of an atom 1

(ii) 0 1+ * 12 1

(iii) shows nucleus and three shells occupied with electron

3abel 1 proton, 1 neutron

1 $1

(iv) 'umber of electrons * 1...0

(b) (i) 3i4uid 1

(ii)

Q R

1$1

...

(c)

1st mar 5 3abel X and a6is with correct unit

nd mar 5 7orrect shape of curve

1$1

1

Temperature/ 7o

Time/s

82

9





+ a) (i) 1

(ii) #tom has achieve stable/octet electron arrangement // has + valence electron 1

b) (i) ; $ < = Æ ;=< $ <

• 7orrect reactant > correct product• ?alance e4uation

1

1

(ii) The nuclei attraction towards the valence electrons is weaer in atom @.More easier for atom @ to lose / release an electron to form a positively charged ion. 1$1

c) (i) 7ovalent bond 1

(ii) 11

(iii) 7annot conduct electricity at any state/ low melting and boiling point/.... 1

(d) Ahow coloured ion//formed comple6 ion//has various o6idation number//act ascatalyst

1

11

(a) Bncreasing of proton number. 1

(b) (i) 'a/sodium, Mg/magnesium .... 1

(ii) #tomic siCe decreases across the period // Deriod . 1

(iii) 1. 'umber of protons in atom increases when across the period.. orce of attraction between nucleus and electrons in the shell is stronger.

1$1

..-(c) 7hlorine more reactive than bromine

AiCe of chlorine atom is smaller than bromine atom7hlorine atom is easier to receive one electron

1$1

(d) #l$ 1(e) (i) Bonic compound 1

(ii) 1$1

11

Y Yx X x

x

x

x xE E.





/ (a) D : li4uid & : solid E : gas 1 $1$1

(b) (i) 1. D can be change to & through freeCing process.. "hen the li4uid cooled, the particles in li4uid lose energy and move slower.. #s temperature drops, the li4uid particles attract tone another and change

into solid

11

1

(ii) 1. D can change to E through boiling.. "hen li4uid is heated, the particles of the li4uid gain inetic energy and

move faster as the temperature increase. The particles have enough energy to overcome the forces between them

and gas is formed

11

1

(iii) 1. E can be change to D through condensation process.. "hen the gas cooled, the particles in gas lose energy and move slower.. Darticles attract one another and change into li4uid

11

1(c) (i) 1. Fniform scale for X5a6is and 5a6is and labelled/siCe of graph plotted G of

graph paper.. Tranfer of point. Amooth curve

111

(ii) 1. ;otted line on the graph from the horiContal line to 5a6is at + 7.o

. #rrow mar freeCing point at + 7o11

(iii) 1. <eat released to sorrounding. Bs balanced when particles comes together to form a solid

11

(iv) Aupercooling 1





Ques!"# N" M$% S'(e)e M$%

(a) (i) #tom E is located in @roup 12, Deriod 1 $ 1(ii) !lectron arrangement of atom E is .+.2.

@roup 12 because it has seven valence electron.Deriod because it has three shells filled with electron

1

11

(b) (i) #toms D and E form covalent bond.To achieve the stable electron arrangement,atom D needs - electrons while atom E needs one electron.Thus, atom D shares - pairs of electrons with - atoms of E,forming a molecule with the formula DE // diagram-

111

1

1

(ii) #tom & and atom E form ionic bond.

!lectron arrangement for atom & is .+.1 and electron arrangement for atom E is .+.2// #tom & has 1 valence electron while atow E has 2valence electronTo achieve a stable (octet ) electron arrangement,atom & donates 1 electron to form a positive ion// e4uation

& &$ $ e

#tom E receives an electron to form ion E //e4uation and achieve a stable5

octet electron arrangement.E $ e E 5

Bon &$ and ion E are attracted together by the strong electrostatic forces5

to form a compound with the formula &E// diagram

1

1

1

11

1

EE

E

E

D

& E

$5 5





Ques!"#

N"M$% s'(e)e M$%

+ (a) 1 represents the nucleon number.8 represents the proton number.

11

(b) #ble to draw the structure of an atom elements X.The diagram should be able to show the following informations:1 '"%%e' #u)e% $# *"s!!"# " *%""# !# (e #u'4eus5 $ (e

'e#%e " (e $")

2 '"%%e' #u)e% $# *"s!!"# " #eu%"# !# (e #u'4eus5 $ (e

'e#%e " (e $")

3 '"%%e' #u)e% $# *"s!!"# " e4e'%"# '!%'u4$!#6 (e

#u'4eus

+ '"%%e' #u)e% " 7$4e#'e e4e'%"#s

Aample answer:

or

1

1

11

e5

e5 e5

e5

e5

e5

e5e5

e5

e5

e5

11*

12#√ 1

√ 2

√ 3

√ 4

e5

e5 e5

e5

e5

e5

e5e5

e5

e5

e5

11* 8 12#





(c) (i) #toms " and form covalent bond.To achieve the stable electron arrangement,atom " contributes - electrons while atom contributes one electron for sharing.Thus, atom " shares - pairs of electrons with - atoms of ,forming a molecule with the formula " // diagram-

11111

(ii) #tom X and atom form ionic bond.!lectron arrangement for atom X is .+.1 and electron arrangement for atom is .+.2To achieve a stable (octet )electron arrangement,atom X donates 1 electron to form a positive ion // e4uation

X X$ $ e#tom receives an electron to form ion //e4uation and achieve a stable octet5

electron arrangement. $ e 5

Bon X$ and ion are attracted together by the strong electrostatic forces to5

form a compound with the formula X// diagram

1

1

1

11

1

(d) The melting point of the ionic compound/ (b)(ii) is higher than that of the covalentcompound/ (b)(i) .This is because in ionic compounds oppositely ions are held by strong electrostaticforces.<igh energy is needed to overcome these forces.Bn covalent compounds, molecules are held by wea intermolecular forces.=nly a little energy is re4uired to overcome the attractive forces.=E The ionic compound/(b)(ii) conducts electricity in the molten or a4ueous statewhereas the covalent compound/(b)(i) does not conduct electricity.This is because in the molten or a4ueous state, ionic compounds consist of freelymoving ionscarry electrical charges.

7ovalent compounds are made up of molecules only

1

1

111

or 1111

1

X

$55

"





9 (a) (i)

1. 7orrect number of shells and valence electrons. ?lac dot or label & at the center of the atom

11

(ii) 1. @roup 1-. There are - valence electrons. Deriod -. #tom consists of shells occupied with electrons

1111

(b) (i) 1. loats and moves fast on the water . H$3IIJ IEX&@ EXFI

. @as liberates / bubbleKany twoL

11

(ii) & $ < = Æ &=< $ <

1. 7orrect reactant and product. ?alanced e4uation

11

(c) (i) 7ompound XAharing electron between atom ? and #

11

(ii) 7hoose any one ionic compound and any one covalent compound.

Melting/boiling point

Bonic compound 7ovalent compound

1..

.

<ighforce of attraction betweenoppositely charged ions arestrong.more heat energy needs toovercome the forces.

lowforce of attraction betweenmolecules are wea.less heat energy needs toovercome the forces.

1111

!lectrical conductivity

Bonic compound 7ovalent compound-.0.

7onduct in molten stateor a4ueous solution.The free moving ions are

able to carry electricalcharges.

'ot conduct electricity.

'eutral molecules are not

able to carry electricalcharges.

111

1

Aolubility

Bonic compound 7ovalent compound

8

2

Aoluble in water.

"ater molecule is polar solvent.

soluble in benCene/ toluene /any organic solvents.The attraction forces betweenmolecules in solute andsolvent are the same.

Q





1 (i)7ompound formed between X

and Molecule formed between and

Types of chemical

bonds

Bonic bond is formed because Xatom donates electrons and

atom receives electrons toachieve stable octet electronarrangement/involve transfer electron

7ovalent bond is formed because and atoms share the

electrons to achieve stableelectron arrangement //Bnovelve sharing of electron

?oiling point andmelting

point

<igh because a lot of heatenergy needed to overcome thestrong electrostatic forces

between ions

3ow because less heat energy isneeded to overcome the wea forces of attraction betweenmolecules

(b)

1.7orrect electron arrangement of ions.7orrect charges and nuclei are shown

. X atom with an electron arrangement of .+. donates valence electrons toachieve the stable octet electron arrangement, .+. X$ ion is formed //X X$ $ e5

-. atom with an electron arrangement of .8 accept electrons to achieve thestable octet electron arrangement, .+. 5 ion is formed // $ e 5 5

0. The oppositely5charged ions, X$ and 5 are attracted to each other by a strongelectrostatic force.

8. #n ionic compound X is formed

11

11

1

11

X

XX

XX

XX

XX

XXXX

XX

XX

XX

$ 5

X$ 5

X

XX

XX

XX

XX

XXXX

XX

XX

XX





(c) 1. # crucible is filled with solid D until it is half full.. Two carbon electrodes are dipped in the solid D and connected to the batteries

using connecting wire.. Awitch is turned on and observation is recorded.-. The solid D is then heated until it melts completely.0. The switch is turned on again and observation is recorded.

8. Ateps 1 to 0 are repeated using solid & to replace solid D.2. =bservations:

D does not light up the bulb in both solid and molten states.& lights up the bulb in molten state only.

D: naphthalene // any suitable answer &: lead(BB) bromide // any suitable answer

1111111111111

11 (a) (i) : .+.2

X : .-

1

1..(ii) atom has 2 valence electrons needs one electron

X atom has - valence electrons ,hence it needs - more electrone$'( $") achieves stable octet electron arrangements($%e e4e'%"#s between them"u% $")s , each contributes 1 electron // K diagram"#e X $") contributes - electrons //KdiagramL5 four single covalent bonds are formed5 the molecular formula is X-

5 diagramK no. of electrons in all the occupied shells in the X

and atoms 5 correctLK sharing of - pairs of single covalent bonds between 1 X atom and - atoms L

11111

1111

1..1

(iii) 7olourless li4uid 1 b) KDrocedures of the e6perimentL

eg.1. #dd a 4uarter of spatula of solid and add into a test tube.. Dour 50 cm of distilled water into the test tube containing the

. Atopper the test tube and shae well.-. Eepeat Ateps 1 to using K named organic solvent eg ether L

0. =bserve the changes and record them in a table

1111

1

. KEesultsL!g

Aolvent =bservation;istilled water 7olourless solution obtainedKnamed organic solventLe.g ether

Aolid crystals insoluble inli4uid

K7onclusionLeg

is insoluble in organic solvent/Knamed organic solventL but soluble in water.

1

1

..2





N" E;*4$#$!"# Su T"$4

1 (a)(i) more reactive 1 0#tomic siCe of bigger than X // The number of shell occupied withelectron atom more than X.

1

The single valence electron becomes further away from the nucleus. 1the valence electron becomes wealy pulled by the nucleus. 1

The valence electron can be released more easily. 1(ii) 'ame : Aodium-'a $ = Æ 'a =Chemical formulae

Balance equation

111

(b) Dut group1 metal into bottle that contain paraffin oil@roup 1 metal readily reacts with air/moisture in atmosphere/ water

11

(c) 'ame : Aodium/any group 1 element

Material : group 1 elements, water,#pparatus : forceps , nife, filter paper, basin, litmus paper.

1

1K procedureL. Dour some water into the basin

-. @roup 1 metal is tae out from paraffin oil using forceps0. # small piece of group 1 element is cut using a small nife8. =il on group 1 element is dried using a filter paper 2. The group 1 element is placed in the basin contain water.+. ;ip a red litmus paper into water

111111

Ma6 0KobservationL9. 7olor of red litmus paper turn to blue 1Kchemical equation ]

Sample answer

'a $ < = Æ 'a=< $ <

Chemical formulae Balance equation 1

1T"$4 20

N" E;*4$#$!"# < T"$4

13 (a) @lucose // naphthalene // any solid covalent compound

covalentBntermolecular forces are wea Amall amount of heat energy needed to overcomes the forces

1111 -

(b) X * .1 X * .

* .2 // * .8 //1. Auitable electron aranggement2. Bonic bond3. to achieve octet electron arrangement4. =ne atom of X donates 1 electron to form ion X $

5. =ne atom of receives an electron to form ion 5

6. Bon X$ and ion are attracted together by the strong5

electrostatic forces

1

1

11111 2

(c) material and apparatus;

compound X 7arbon electrode, cell, wire, crucible,,

bulb/ammeter/galvanometer 1





Procedure

# crucible is half fill with solid X powder ;ipped two carbon electrode7onnect the electrodes with connecting wire to the battery and

bulb=bserved whether bulb glow

<eated the solid X in the crucible=bserved whether bulb glowObservation

Aolid X 5 bulb does not glowMolten X 5 bulb glow

iagram

!unctional diagram

"abeled

11111

1

11 9

TOTAL 20

SET 1:CHEMICAL FORMULAE AND EQUATIONS

Ques!"# N" M$% s'(e)e M$%

1 (a) M"4$% )$ss is the mass of a substance that contains one mole of the substance.!6ample : Molar mass of one mole of magnesium is -gmol 51 .

1

(b) Aubstance M"4$% )$ss 5 6)"4-1

' 1-6 * +

7= 1$(18) * --

< A (1)$ * -

< = (1)$18 * 1+

-

(c) Mole of water * .9/ 1+ * .0

'umber of molecules * .0 6 8. 6 1

* . 6 1 // 6 1

Mole of carbon dio6ide * . / -- * .0

1

1

1

1





'umber of molecules * .0 6 8. 6 1

* . 6 1 // 6 1

'umber of molecule is simmilar

1

2 (a) (i) Iolume 7= * .1 mol 6 -dm mol 51 * .- dm 1

(ii) Mass of 7= * .1 mol 6 -- gmol 51 * -.- g 1

(iii) 'umber of molecules * .1 mol 6 8. 6 1 1

(iv) 'umber of atoms * 8. 6 1 6 * 1.+8 6 1

1$1

(b) (i) <eating, cooling and weighing processes are repeated a few times until aconstant mass is obtained.

(ii)7ompound #nhydrous 7o7l < =

Mass/g (-.151.0)g* .8 g

(8.85-.1)g* .18 g

'umber of moles .8/1 * . .18/1+ * .1

Eatio of moles ./. * 1 .1/. * 8

Aimplest ratio of moles 1 8

1 mole of 7o7l combines with 8 moles of < =

Therefore, the molecular formula of hydrated cobalt(BB) chloride

crystal is 7o7l .8< =.

<ence, the value of 6 in 7o7l .6< = is 8.

1

1

1

(iii) Dercentage of water

*8(1+)(/0.0)09

)1+(8

++

6 1%

* 1+ 6 1% * ++=+

1

1

Total 1

(a) (i) concentrated sulphuric acid 1

(ii) Cin and hydrochloric acidK any suitable metal and acid L 1

(iii) n $ <7l Æ n7l $ <

(b) (i) Mole of o6ygen * -8.0 5 -0.10

18* 1. * 00

18

1





(ii) Mole of copper * -0.10 5 -.08-

* -.+ * 008-

1

1

(iii) !mpirical formula * 7u= 1

(c) (i) 7ollect the hydrogen gas in a test tubeDut a burning wooden splinter at the mouth of the test tubeH1E AEA IEX&@ H AFE@X<@

111

(ii) To avoid the hot copper react with o6ygen/air 1

(iii) Eepeat heating, cooling and weighing processes until a constant mass obtained. 1

Total 11

- (a) (i) Db('= ) 1(ii) #g7l 1

(b) (i) Db$ $ 7l5 Æ Db7l

7orrect formula for reactants and product?alance ionic e4uation

1$1

(ii) &ualitative aspect :3ead(BB) nitrate and sodium chloride are the reactants and lead(BB) chloride and sodium nitrate are the products //3ead(BB) nitrate solution reacts with sodium chloride solution to form lead(BB)

chloride precipitate and sodium nitrate solution.

&uantitative aspect :=ne mole of lead(BB) nitrate reacts with mole sodium chloride to

produce 1 mole of lead(BB) chloride and mole of sodium nitrate.

1

1

(c) (i) 2 Db('= ) Æ 2 Db= 8 + '= 8 = 1

7ompound 7olour of theresidue when

hot

7olour of theresidue when

cold

Db= B%"># .e44">

@ases 7olour of the gas released

'= ?rown

= 7olourless

1

1

1

Total 1





N" E;*4$#$!"# M$%

(a) (i) #l$ , Db -$ 1$ 1(ii) #luminium o6ide

3ead(BI) o6ide1 $ 1

(b) (i) (7< =)n * 8

1n $ n $ 18n * 8n * Molecular formula * 7 < = //7< 7==< -

1

11

(ii) 7a7= $ 7< 7==< (7< 7==) 7a $ < = $ 7=

(c) (i) 1.@reen solid turn ?lac . 3ime water becomes cloudy

11

(ii) 7u7= 7u= $ 7= 1 $ 1

(iii) 1. 1 mol of copper(BB) carbonate decomposed into 1 mol of copper(BB) o6ide and1 mol of carbon dio6ide. copper(BB) carbonate is in solid state, copper(BB) o6ide is in solid state and

carbon dio6ide is in gaseous state

1

1

(iv) 1. 'o. of mole for 7u7= * 1.- / 1- * .1 mol. 1 mol of 7u7= produces 1 mol of 7u=

Therefor 'o. of mole for 7u= * .1 mol. Mass of 7u= * .1 mol X + g mol51 * + g

11

1

(v) Mass of o6ygen is .+gAimplest mol ratio : 7u : = * ./8- : .+/18 * 1 : 1

11

20

Mar

/

(a) (i) !mpirical formula of a compound is a formula that shows the simplest wholenumber ratio of each atoms of each element in a compound. 1

(ii) (ii)Aubstance !mpirical formula

7 <1 + 7 <0 -

< A= - < A= -

1

1





(b)!lement 7arbon <ydrogen =6ygen

Dercentage (%) 8.2 1.- 2.09Mass/ g 8.2 1.- 2.09Mole 8.2/1

* 0.121.-/1* 1.-

2.09/18* 1.2

Aimplest moleratio

0.12/1.2*

1.-/1.2* 8

1.2/1.2*1

!mpirical formula * 7 < = 8

n K7 < = L * 118 8

K (1) $ 8(1) $ 18 L n * 1180+ n * 118

n *

Molecular formula * 7 < =8 1

1

1

1

1

1

(c) Drocedure :

1. 7lean magnesium ribbon with sand paper.."eigh crucible and its lid.. Dut magnesium ribbon into the crucible and weigh the crucible with its lid.-. <eat strongly the crucible without its lid.0. 7over the crucible when the magnesium starts to burn and lift/raise the lid alittle at intervals.8. Eemove the lid when the magnesium burnt completely.2.<eat strongly the crucible for a few minutes.+.7ool and weigh the crucible with its lid and the content.9. Eepeat the processes of heating, cooling and weighing until a constant mass

is obtained.1.Eecord all the mass.

Tabulation of result :

;escription Mass/ g7rucible $ lid a7rucible $ lid $ magnesium b

7rucible $ lid $ magnesium o6ide c

1

1

!lement Magnesium =6ygenMass / g b5a c5bMole b5a/ - c5b / 18Aimplest ratio of mole

6 y

!mpirical formula * Mg =6 y

1

1

1

Ma611

Total





'o Aub T2. (a) 1. !mpirical formula is the chemical formula that shows the simplest ratio of

atoms of each element in the compound.. Molecular formula is the formula that shows the actual number of atoms of

each element in the compound.. !6ample : empirical formula of ethene is 7< and the molecular formula is

7 < -

11

1

(b)(i)

(ii)

!lement 7arbon <ydrogen =6ygen

Dercentage -. 8.88 0.

'umber of moles

-1

/.//=

8.881

8.88=0/.//

18 /.//=

Eatio of moles 1 1

!mpirical formula is 7< =n(7< =) * 1+

1n $ n $ 18n * 1+n * 1+

n*8molecular formula * 7 < =8 1 8

1

1

1

11 0

(c)(i) Magnesium is more reactive than hydrogen//Dosition of magnesium is abovehydrogen in the reactivity series

1

(ii) 3ead(BB) o6ide / Atanum o6ide / iron o6ide / copper(BB) o6ide

(iii) 1. 7lean K0 10L cm magnesium ribbon with sandpaper and coil it.. "eigh an empty crucible with its lid.. Dlace the magnesium in the crucible and weigh again.-. Eecord the reading.0. <eat the crucible very strongly.8. =pen and close the lid very 4uicly.2. "hen burning is complete stop the heating+. 3et the crucible cool and then weigh it again9. The heating, cooling and weighing process is repeated until a constant mass is

recorded.1.

;escription Mass(g)

7rucible $ lid

7rucible $ lid $ Mg / n / #l

7rucible $ lid $ Mg= / n= / #l =

1

Total





SET 2 :ELECTROCHEMISTR.

Ques!"#N"

M$% s'(e)e M$%

1(a) !lectrical to chemical energy / #enaga ele$tri$ $epada tenaga $imia 1

(b) Dure copper / %uprum tulen 1(c) 7u$ and <$ 1

(d)(i)(ii)

?ecome thicer / brown solid formed Bertambah tebal & pepe'al perang terbentu$

7u$ $ e Æ 7u

11

(e) ?lue solution remain unchanged // the intensity of blue solution is the same. "arutan biru tida$ berubah && $eamatan warna biru larutan adalah sama(

(i) the concentration of 7u$ ions remains the same.$epe$atan ion $uprum)**+ tida$ berubah

(ii) the rate of ioniCed copper at the anode same as the rate of discharged copper(BB)ion at the cathode .

$adar pengionan $uprum di anode sama dengan $adar ion $uprum)**+dinyahcas$an di $atod

1

1

1

(f) =6idation / pengo$sidaan

7opper atom released electron to form copper(BB) ion. ,tom $uprum mender-ar$an & membebas$an ele$tron menghasil$an ion $uprum)**+(

11

(g) !lectroplating of metal // e6traction of metal Penyaduran logam && penge$stra$an logam

1

Total 11

(a)(i) 7hloride ion / 7l , hydro6ide ion / =< , sodium ion / 'a and hydrogen ion / <5 5 $ .

*on $lorida & Cl / ion hidro$sida &O0 / ion natrium / a dan ion hidrogen & 0 2 2 . .

1(ii) 7l . The concentration of chloride ion is higher than hydro6ide ion.5

7l . %epe$atan ion $lorida lebih tinggi daripada ion hidro$sida5

1 $ 1

(iii) 7l5 Æ 7l $ e 1(b)(i)

unctional 13abel 5 1

11

(ii) 5 place lighted splinter at the mouth of the test tube containing hydrogen gas5 NAEAO IEX&@ AFE@X<@5 "eta$$an $ayu u'i menyala $e dalam tabung u'i berisi gas hydrogen

5 ?X&P3 NAEAO "eFQaI3=

1

1

(iii) 5 Aodium ion and hydrogen ions move to the cathode, hydrogen ion is selectivelydischarged

5 hydrogen ion is lower than sodium ion in the !lectrochemical Aeries.

5 *on natrium dan ion hydrogen bergera$ & tertari$ $e $atod , ion hidrogen terpilihuntu$ nyahcas & discas

5 *on hidrogen terleta$ di bawah ion natrium dalam Siri 3le$tro$imia

11

Total 11

7arbon electrodes 3le$trod $arbon

Aodium sulphatesolution

"arutan natrium

sulfat #

=6ygen gas4as o$sigen

<ydrogen gas4as hidrogen






Ques!"#

N"

M$% s'(e)e M$%

(a) 7u$ , <$ 1(b) 7arbon electrode which connect to copper electrode in cell #.

?ecause o6idation taes place

3le$trod $arbon yang disambung $epada ele$trod $uprum dalam sell , %erana proses pengo$sidaan berla$u

11

(c)(i) X silver electrode / ele$trod argentum impure silver electrode / ele$trod argentum ta$ tulen

11

(ii) #g$ $ e Æ #g 1(d)(i) 5 The electrode become thinner

5 Ailver atom ioniCed / silver atom o6idiCed to form silver ion5 ele$trod se-ar$in nipis

2 atom argentum mengion & atom argentum dio$sida$an membentu$ argentum ion(

11

(ii) : #g Æ #g$ $ e : #g$ $ e Æ #g

11

(e) The waste chemicals emitted contain poisonous heavy metal ions and cyanide ions / alter

the p< of water. Bahan buangan $imia dibebas$an mengandungi logam berat yang beracun dan sianid &

mengubah nilai p0 air

1

11

Ques!"#

N"

M$% s'(e)e M$%

-(a)(i) 3ead(BB) ion// Db , bromide ion// ?r $ 5

*on plumbum(BB)// Db , ion bromida// ?r $ 51

(ii) Aodium ion // 'a , hydrogen ion// < , sulphate ion// A=$ $-5, hydro6ide ion//=<5

ion natrium && a / ion hidrogen&& 0 / ion sulfat && SO

. .

5

62

/ ion hidro$sida &&O0

21

(b)(i) 3ead / Plumbum 1

(ii) Db$ $ e Æ Db 1

(iii) ?rown gas / 4as berwarna perang 1

(c)(i) hydro6ide ion / ion hidro$sida 1

(ii) #node : =6ygen gasanod : 4as o$sigen

7athode : hydrogen gas %atod : gas hidrogen

1

1

(iii) Aodium nitrate solution // sulphuric acid

"arutan natrium nitrat && asid sulfuri$ (#ny suitable electrolyte) 1

9





Eubric Mar0(a) (i) &, E, A , 7u 1

R(ii) positive terminal : 7u

Dotential difference : .2 IA is higher than 7u in the !lectrochemical Aeries

111

..... (b) (i) positive terminal : copper / 7u 'egative terminal : Metal D

(ii) metal D : inc / n // Magnesium/Mg(any suitable metal)Aolution & : inc sulphate // magnesium sulphate(any suitable electrolyte)

111

1

..... -

(c) (i) anode : greenish yellow gascathode : colourless gas (bubbles)

11R

(ii) gas X : hydrogengas : chlorine 11R

(iii)

#node 7athodeBons move to / ionattracted to

<ydro6ide ion/=<5

7hloride ion/7l5<ydrogen ion/< ,$

Dotassium ion/Q $

Bons selectivelydischarged

7l5 <$

Eeason 7oncentration 7l higher

5

than =<5 Dosition of hydrogenion/< is lower than$

potassium ion/Q in the$

!lectrochemical Aeries.<alf e4uation 7l5 Æ 7l $ e <$ $ e Æ <

1$1

1$1

1$1

1$1

RTotal 20

Ques!"#

N"

M$% s'(e)e M$%

8(a) (i) Aubstance E : @lucose / ethanol (any suitable covalent compound)Aubstance A : Aodium chloride solution ( any salt solution / acid / alali) 11R

(ii) 1. A conducts electricity but E does not. A has free moving ions // ions free to move. E consists of molecules / no free moving ions

111

R(b) (i) negative terminal : Cinc

positive terminal : copper 11

R(ii) 1. Cinc electrode become thinner

. n Æ n$ $ e11

R(iii) 1. the potential difference decreases

. iron is lower than Cinc in the !lectrochemical Aeries //iron is less electropositive than Cinc // distance between iron and

11





copper is shorter than distance between Cinc and copper in the!lectrochemical Aeries R

(c) (i) Aample answer 3ead(BB) bromide / lead(BB) iodide /sodium chloride/sodium iodide(any suitable ionic compound)r : substance that decompose when heated.

!6ample : lead(BB) nitrate, lead(BB) carbonate

1

(ii)

;iagram:unctional3abel

=bservation:#node : brown gas7athode: grey solid

<alf e4uation:#node : ?r 5 Æ ?r $ e7athode : Db $ $ e Æ Db

Droduct:#node : lead7athode : bromine gas

11

11

11

11

R

T"$4 20

Ques!"#

N"

M$% s'(e)e M$%

2(a) Aample answer Ailver nitrate solution

unctional 13abel 5 1

#node : #g Æ #g $ e$

7athode : #g$ $ e Æ #g

1

11

1

1R(b) 1. metal X is more electropositive than copper // X is higher than copper in the

!lectrochemical Aeries 1

7arbon electrodes 3le$trod $arbon

DbB // Db?r //

'a7l

<eat

Panas$an

'ote :=bservations and half5e4uations are

based on the substance suggested.

Ailver nitrate solutionBron spoonAilver





Ques!"#

N"

M$% s'(e)e M$%

(a) # reaction which involves o6idation and reduction occur at the same time 1(b) (i) green to yellow/brown 1

(ii) o6idation 1

(iii) e$

: )<$

$ e 1(iv) 1(c) (i) magnesium 1

(ii) Mg $e$ : S $ $ e 1(iii) $ to 1

(d) 1. label for !%"#, >$e% $# ";?6e#

. ioniCation of iron in the water droplet (at anode). flow of electron in the iron to the edge of water droplet

"ater droplet =

Bron

111

11

3 (a) Eeaction # : #" a redo6 reactionEeaction ? : a %e"; reaction

11

Eeaction #: 'o change in o6idation number

Eeaction ?:=6idation number of magnesium changes/increases from 0 to 82 //=6idation number of Cinc changes/decreases from 82 to 0

1

1.....+

(b) (i) =6idation number of copper in compound D is $ 2=6idation number of copper in compound & is 8 1

11.....2

(ii) 7ompound D : 7opper(II) o6ide

7ompound & : 7opper(I) o6ide=6idation number of copper in compound D is $=6idation number of copper in compound D is $1

1

111.....+

(iii) • Aubstance that is o6idised : <

• Aubstance that is reduced : 7u=• =6idiCing agent : 7u=• Eeducing agent : <

1111.....+

(c) (i) X, , 1

: 7opper : 3eadX : Magnesium

111.....3

e Æ e$ $e

eÆeÅ





Mg $ = : SX $ = :

KCorrect formulae of reactants and product LK Balanced equationL

11.....2

TOTAL 20

+ (a) (i) Bron(BB) ion releases / loses one electron and is o6idised to iron(BBB) ion//=6idation number of iron in iron(BB) ion increases from $ to $.

Bron(BB) ion undergoes o6idation, Bron(BB) ion acts as a reducing agent

1

1

(ii) Bron(BB) ion receives/ gain one electron and is reduced to iron.//=6idiCation number of iron in iron(BB) iron decreases from $ to .iron(BB) ion undergoes reduction, Bron(BB) ion acts as an o6idising agent

1

1

(b) e -g -g +→

+

=6idation number of magnesium increases from to $

magnesium undergoes o6idationCueCu →+

+

o6idation number of copper in copper(BB) ion decreases from $ to copper(BB) ion undergoes reduction

11

1

111

(c) #t the negative terminal:Bron(BB) ion release / lose one electron andis o6idised to iron(BBB) ion.e$ Æ e$ $ eThe green coloured solution of iron(BB) sulphate turns brown.e$ act as a reducing agent.

#t the positive terminal:?romine molecules accepts electrons andis reduced to bromide ions, ?r 5

?r $ e Æ ?r 5

The brown colour of bromine water turns colourless.?romine acts as an o6idising agent

11111

11111


(a) 1. Mg/#l/e/Db/n

2. Magnesium undergoes o6idation as o6idation number of magnesiumincreases from to $ and

3. 7opper (BB) o6ide undergoes reduction as o6idation number of copper incopper(BB) o6ide decreases from $ to

4. =6idation and reduction occur at the same time.

1111

(b) !6periment B

1. e$ ion present

2. Metal X lower than iron in the !lectrochemical Aeries //Metal X is less electropositive than iron3. Bron atoms releases electrons to form iron(BB) ions

1

11





!6periment BB1. =< ion present5

2. Metal higher than iron in the !lectrochemical Aeries //Metal is more electropositive than iron

3. #tom releases electrons to form n$ ions4. "ater and o6ygen gain electron to form =< ion //5

< = $ = $ -e :

-=<5

1111

Ma6 (c) Drocedure

1. =ne spatula of copper(BB)o6ide powder and one spatula of carbon powder is placed into a crucible

. The crucible and its content are heated strongly. The reaction and the changes that occur are observed-. Ateps 1 to are repeated by replacing copper(BB)o6ide powder with Cinco6ide powder and magnesium o6ide powder.

=bservation

Mi6ture =bservation7arbon andcopper(BB)o6ide

The mi6ture burns brightly.The blac powder turns brown

7arbon and Cinco6ide

The mi6ture glows dimly.The white powder turns grey.

7arbon andmagnesium o6ide

'o 7hanges

1111

1$1

!6planation7arbon can react with copper(BB)o6ide and Cinc o6ide

7arbon more reactive than copper and Cinc / carbon is above copper and Cinc inthe Eeactivity Aeries7arbon cannot react with magnesium o6ide7arbon less reactive than magnesium / carbon is below magnesium inthe Eeactivity Aeries

1111

8 Aample answer

(a) Magnesium/#luminium/Cinc/iron/lead 1Magnesium dissolve//The blue colour of copper(BB)sulphate solution become paler // brown solid deposited 1

S:S $ $ e 17u$ <: >X 1=6idising agent5 7u$ ion / copper(BB) sulphate 1Eeducing agent5 Mg 1..8

(b) sample answer

Db('= ) $ QB → Dbl $ Q'= 1

=6idation number: $2 8 -2 81 -1 82 -1 81 8 -2 1





no changes of o6idation number of all elements in the compounds of reactantsand products. 1

'eutraliCation 1...-

(c ) sample answer

KMaterial : #ny suitable o6idiCing agent(e6ample : acidified potassium manganate(IBB) solution,acidified potassium dichromate(IB) solution, chlorine water, bromine water),any suitable reducing agent(e6ample : potassium iodide solution, iron(BB) sulphate solution)and any suitable electrolyteL 1

K #pparatus : F5tube , carbon electrodes , connecting wires and galvanometerL 1

;iagramunctional 1

3abelled 1

Drocedure1 Aulphuric acid is added into a F5tube until 1/ full 1 ?romine water is added into one end of the F5tube while potassium

iodide solution is added into the other end of the F5tube 1 carefully 1- Two carbon electrodes connected by connecting wires to a galvanometer

are dipped into the two solution at the two ends of the F5tube. 1

=bservation

The colour of bromine water change from brown to colourless//The colour of potassium iodide solution change from colourless to yellow/brown//The needle of the galvanometer is deflected 1

=6idation reaction : ?r <: %F5 1

Eeduction reaction: B : ,5 $ e 1

Ma6 : 1





SET 3 :ACIDS, BASES AND SALTS

Ques!"#

N"

M$% s'(e)e M$%

1 (a)(i) Dropanone / MethylbenCene / Kany suitable organic solventL 1

(ii) "ater 1(b)(i) Molecule 1

(ii) Bon 1

(c) 1. ?eaer # : 'o observable change?eaer ? : @as bubbles released

. < ion does not present in beaer # but < ion present in beaer ? //$ $

<ydrogen chloride in beaer # does not show acidic properties buthydrogen chloride in beaer ? shows acidic properties

1

1

(d)(i) 1. 7orrect formula of reactants and products

. ?alanced e4uation

S $>= : S>= $ <

1

1

(ii) 1. Mole of <7l. Mole ratio. #nswer with correct unit

Mole <7l * 45v94

5444// .0

mol <7l reacts with 1 mol Mg.0 moles <7l reacts with .0 moles Mg

Mass Mg * .0 6 - // .8 g

111

TOTAL 10

Ques!"#

N"

M$% s'(e)e M$%

(a)(i) Aubstance that ioniCe / dissociate in water to produce < ion$ 1

(ii) 1

(iii) 1. 7oncentration of acid / < ion in Aet BB is lower than Aet B$

. The lower the concentration of < ion the higher the p< value$11

(iv) 1. !thanoic acid is wea acid while hydrochloric acid is strong acid. !thanoic acid ionises partially in water to produce low concentration of < ion$

while. hydrochloric acid ionises completely in water to produce high concentration of < $

ion

11

1

(b)(i) 1. The p< value of sodium hydro6ide in volumetric flas ? is lower than #

. 7oncentration of sodium hydro6ide / =< ion in volumetric flas ?5

is lower than #

1

1






(ii) 1. Mole of 'a=<. Mass of 'a=< with correct unit

Mole 'a=< * 445v944

5444// .0

Mass 'a=< * .0 6 - g // . g

11

(iii) .1 6 I * . 6 1 // cm

T=T#3 1

Ques!"#

N"

M$% s'(e)e M$%

(a) Din to colourless 1

(b) Dotassium nitrate 1

(c)(i) <'= . $ : . 1 $ < = 1

(ii) 1. Mole of <'= // Aubstitution. Mole ratio. 7oncentration of Q=< with

Mole <'= * 49v64

5444// .1

.1mole <'= reacts with .1 mole Q=<

Molarity Q=< * 445v5444

69

mol dm5 // .- mol dm 5

111

(d)(i) 1 cm 1

(ii) 1. Aulphuric acid is diprotic acid but nitric acid is monoprotic acid // 1 mole of sulphuric acid produce moles of < ion but 1 mole of nitric acid produce 1 mole$

of < ion$

. 7oncentration of < ion in sulphuric acid is double compare to nitric acid$

. Iolume of sulphuric acid needed is half

1

11

T=T#3 1

Ques!"#

N"

M$% s'(e)e M$%

- (a) Bonic compound formed when < ion from an acid is replaced by a metal ion or $

ammonium ion1

(b) Db('= ) 1

(c) To ensure all the nitric acid reacts completely 1

(d)(i) 1. 7orrect formula of reactants and products. ?alanced e4uation

<$ ! : ! $ $ < =

11





(ii) 1. Mole of acid. Mole ratio. #nswer with correct unit

Mole <'= * 54v94

5444// .0

.0 moles <'= produce .0 moles salt @

Mass of salt @ * .0 6 1 g // +.20 g

111

(e) 1. #dd cm dilute sulphuric acid followed by cm of Bron(BB) sulphate solution

Alowly add concentrated sulphuric acid by slanted the test tube. Then turn it upright.. ?rown ring is formed.

11

T=T#3

Ques!"#

N"

M$% s'(e)e M$%

0 (a)(i) Aalt " : 7opper(BB) carbonateAolid X : 7opper(BB) o6ide 11

(ii) 1. low gas into lime water . 3ime water turns cloudy / chaly.

11

(iii) 'eutralisation

(iv) 1. 7orrect formula of reactants and products. ?alanced e4uation

7u= $>= : >X>= $ < =

11

(b) 7ation : 7u$

ion // copper(BB) ion#nion : 7l ion // chloride ion5 11

(c)(i) #g$ $ 7l5 : US>= 1

(ii) ;ouble decomposition reaction 1

T=T#3

Ques!"#

N"

M$% s'(e)e M$%

8 (a)(i) @reen 1

(ii) ;ouble decomposition reaction 1

(b)(i) 7arbon dio6ide 1

(ii) 7u7= : >X > 1

(iii) 1. unctional apparatus. 3abel

11

(c)(i) Aulphuric acid // < A= - 1

<eat

7opper(BB) carbonate

3imewater





(ii) 1. Mole of 7u7=

. Mole ratio. #nswer with correct unit

Mole 7u7= * 568

568// .1

.1 moles 7u7= produces .1 mole 7u=

Mass 7u= * .1 6 + g // + g

111

T=T#3

2 (a) 1. Iinegar . "asp sting is alali. Iinegar can neutraliCe wasp sting

111

(b) 1. "ater is present in test tube X but in test tube there is no water.

. "ater helps ammonia to ionise // ammonia ionise in water . =< ion present5

-. =< ion causes ammonia to show its alaline properties5

0. "ithout water ammonia e6ist as molecule // without water =< ion does not5

present8. "hen =< ion does not present, ammonia cannot show its alaline properties5

1

1111

1

(c) 1. Aulphuric acid is a diprotic acid but nitric acid is a monoprotic acid. 1 mole of sulphuric acid ioniCe in water to produce two moles of < ion but 1 mole$

of nitric acid ioniCe in water to produce one mole of < ion$

. The concentration of < ion in sulphuric acid is double / higher $

-. The higher the concentration of < ion the lower the p< value$

11

11

(d)(i) 1. Mole of Q=<. Molarity of Q=< and correct unit

Mole Q=< * 584

9:// .0

Molarity * 469 v 5444

694mol dm5 // 1 mol dm5

11

(ii) 1. 7orrect formula of reactants. 7orrect formula of products. Mole of Q=< // Aubstitution

-. Mole ratio0. #nswer with correct unit

<7l $ . $ : . >= $ =

Mole Q=< * 5 v 69

5444// .0

.0 mole Q=< produce .0 mole Q7l

Mass Q7l * .0 6 2-.0 g // 1.+8 g

1111

1

T=T#3





Ques!"#

N"

M$% s'(e)e M$%

+ (a)(i) 1. Db7l

. ;ouble decomposition reaction11

(ii) 7opper (BB) chloride :7opper(BB) o6ide / copper(BB) carbonate , <ydrochloric acid

3ead (BB) chloride :3ead (BB) nitrate solution , sodium chloride solution ( any solution that contains 7l ion)5

1 $ 1

1 $ 1

(b)(i) 1. A * Cinc nitrate. T * Cinc o6ide. F * nitrogen dio6ide-. " * o6ygen

1111

(ii) n('= ) → n= $ -'= $ = 1$1

(c)(i) 1. ?oth a6es are label and have correct unit

.Acale and siCe of graph is more than half of graph paper

. #ll points are transferred correctly

111

(ii) 1

(iii) Mole ?a$ ion * 4 9 v 9

5444// .0

Mole A=-5 ion * 4 9 v 9

5444// .0

?a$ ion : A= -5 ion

.0 : .0 //1 : 1

1

1

1

(iv) ?a$ $ A=-5 : %;8 - 1

T=T#3

Ques!"#

N"

M$% s'(e)e M$%

9 (a) 1. <7l // <'=

. 1 mole acid ionises in water to produce 1 mole of < ion$

. < A= -

-. 1 mole acid ionises in water to produce moles of < ion$

1111

(b) 1. Aodium hydro6ide is a strong alali. #mmonia is a wea alali. Aodium hydro6ide ionises completely in water to produce high concentration of =<5

ion-. #mmonia ionises partially in water to produce low concentration of =< ion5

0. 7oncentration of =< ion in sodium hydro6ide is higher than in ammonia5

8. The higher the concentration of =< ion the higher the p< value5

111111

0





(c) 1. Iolumetric flas used is 0 cm

. Mass of potassium hydro6ide needed * .0 X 08 * 1- g. "eigh 1- g of Q=< in a beaer -. #dd water 0. Atir until all Q=< dissolve8. Dour the solution into volumetric flas 2. Einse beaer, glass rod and filter funnel.+. #dd water 9. when near the graduation mar, add water drop by drop until meniscus reaches the

graduation mar 1. stopper the volumetric flas and shae the solution

111111111

1T=T#3

Ques!"#

N"

M$% s'(e)e M$%

1 (a)(i) Aubstance 7 : @lacial ethanoic acidAolvent ; : Dropanone K or any organic solventL

11

(ii) Aolution !1. !thanoic acid ionises in water . 7an conduct electricity because presence of freely moving ions. blue litmus paper turns to red because of < ions is present$

Aolution -. !thanoic acid e6ist as molecules0. 7annot conduct electricity because no freely moving ion8. 7annot change the colour of blue litmus paper because no < ion$

111

111

(b) 1. Measure and pour K51 cm L of K.15. mol dm LCinc nitrate solution into a 5

beaer

. #dd K51 cm L of K.15. mol dm Lsodium carbonate solution 5

. Atir the mi6ture and filter -. Einse the residue with distilled water 0. n('= ) $ 'a 7= →n7= $ 'a'=

8. Measure and pour K51cm Lof K.151.mol dm Lsulphuric acid into a beaer 5

2. #dd the residue/ Cinc carbonate into the acid until in e6cess+. Atir the mi6ture and filter 9. <eat the filtrate until saturated / 1/ of original volume1. 7ool the solution and filter 11. ;ry the crystal by pressing between two filter papers1. n7= $ < A= -→ nA=- $ < = $ 7=

1

11111111111

T=T#3





SET 3 :RATE OF REACTION

Ques!"#

N"

M$% s'(e)e M$%

1(a)(i) Aet BB 1

(ii) ,ble to draw the graph with these criterion7

1 3abelled a6is with correct unit. Fniform scale for X and a6is > siCe of the graph is at least half of the graph

paper . #ll points are transferred correctly-. 7urve is smooth.

11

11

(b)(i) Aet B :1.Tangen shown in graph correctly.Eate of reaction * .19 cm s 51 ( $5 .0)

Aet BB :1.Tangen shown in graph correctly.Eate of reaction * . cm s 51 ($5 .0)

11

11

(ii) #dd catalystBncrease the temperatureFse smaller siCe/ metal powder Bncreases the concentration of acid// ;ouble the concentration of acid but half volume

K#ny twoL

11

Ques!"#

N"

M$% s'(e)e M$%

2 (a) 1. 7orrect formulae of reactants and product. ?alanced e4uation

7a7= $ <'= : >;1 ) $ 7= $ < =

11

(b)unctional diagram3abel

11

(c) 1. Mole of nitric acid. Mole ratio. #nswer with correct unit

'umber of moles of <'= * . X 0 * .1 mol //1 mol of <'= produce 1 mol of 7=

.1 mol of <'= produce .0 mol of 7=

111

'itric acid

7alcium carbonate

"ater






Ma6imum volume of 7= * .0 6 - * .1 dm // 1 cm

(d) !6periment B * .1 X 1 // . cm s // 51

1 X 8//.1 //.1 dm min 51

1

!6periment BB * .1 X 1 // .- cm s 51 //0 X 8

// .1 // .- dm min 51

0

1

1

(e)(i) Eate of reaction in !6periment BB is higher than B 1

(ii) 5 The siCe of calcium carbonate in !6periment BB is smaller than !6periment B //calcium carbonate powder in !6periment BB has a larger total surface area e6posed tocollision than !6periment B.5 The fre4uency of collision between between calcium carbonate and

hydrogen ion in !6periment BB is higher than !6periment B.5 The fre4uency of effective collision s in !6periment BB is higher than !6periment B

1

1

1

Ques!"#

N"

M$% s'(e)e M$%

3(a)

5Total surface area of smaller pieces wood is larger/bigger/ greater than the bigger pieces of wood5 More surface area e6posed to air for burning

11

(b)(i) 1. !6periment BB. Dresent of catalyst /manganase(BI) o6ide in !6periment B

11

(ii) 1.7orrect formulae of reactants and product.?alanced e4uation

< = : < = $ =

11

(iii)

1. #rrow upward with energy label ,two levels and position of reactant and products are correct

. 7urve of !6periment B and e6periment BB are correct and label. #ctivation energy of e6periment B and e6periment BB are shown and labelled

111

(c)(i) 1.7orrect formulae of reactants and product.?alanced e4uation

n $ <7l Æ n7l $ <

11

(ii) 'o. of mol <7l * 0 X .0 // .01

1

!nergy

< =

!a

< = $

=

!a J





mol <7l : 1 mol <

.0 mol <7l : .10 mol <

Iolume of < * .10 6 - // .dm // cm

1

1

(iii) 1. #dd e6cess Cinc powder with 1.0 cm of 1 mol dm hydrochloric acid . 5

. #t the same temperature

=E

1. #dd e6cess Cinc powder with 0 cm of .0 mol dm hydrochloric acid 5

. #t the higher temperature //present of catalyst

1

1

1

1

(iv) 1. Eate of reaction using sulphuric acid is higher . The concentration of < ion in sulphuric acid is higher $

. Ma6imum volume of gas collected is double-. The number of mole of < ion in sulphuric acid is double$

1111

20

Ques!"#

N"

M$% s'(e)e M$%

+ (a) 1. Temperature in refrigerator is lower than in cabinet. The activity of microorganisme (bacteria) in refrigerator is lower than in

refrigerator . The amount of to6in produced in the refrigerator is less then in the itchen

cabinet.

11

1

(b)(i) 1 7orrect formula of reactants and products2 Mol of sulphuric acid3 Mole ratio

+ Iolume and ratio

n $ < A= - 5555555Æ nA=- $ <

'o. =f mol < A= * 1 X 0/1 // .0 -

1 mol of < A= - : 1 mol of <

.0 mol of < A= - : .0 mol of <

Iolume of < * .0 6 - dm //1. dm //.0 6 -//1 cm

1

1

1

1

(ii) !6periment B * 1 // 10 cm s 51

+!6periment BB * 1 // 2.0 cm s 51

18!6periment BBB * 8 // .0 cm s 51

-

11

1

(iii) !6p B and BB1.Eate of reaction of !6pt B is higher .The siCe of Cinc in !6pt B is smaller .Total surface area of Cinc in !6pt B is bigger/larger -.The fre4uency of collision between @!#' $") $# (?%"6e# !"#5H in !6pt B is8

higher

0. The fre4uency of effective collision in !6p B is higher

1

111

1





!6p BB and BBB1. Eate of reaction in !6pt BB is higher .The concentration of sulphuric acid/ < ion in !6p BB is higher $

. The no. of < per unit volume in !6pt BB is higher/greater in !6pt BB//$

-. The fre4uency of collision between Cinc atom and < in !6pt BB is higher $

0. The fre4uency of effective collision in !6pt BB is higher

11111

Ques!"#

N"

M$% s'(e)e M$%

a)(i)

' $ < 5555555Æ '< 1 $ 1

(ii) Temperature : -0 V >Dressure : atm7atalyst : Dowdered iron// Bron filling

K #ny twoL

1

1

(b)(i) 38ample of acid

Aample answer :<ydrochloric acid / <7l// Aulphuric acid // 'itric acid

Correct formula of reactant and product

BalanceAample answer $>= S : S>= $ <

11

1

(ii) 1. !6periment B : cm / 8 s // . cm s 51

. !6periment BB : cm / 0 s // .- cm s 511

1

(iii) (7atalyst)!6periment 1:

1.Dour /measure (051) cm of (.15 mol dm 5

) hydrochloric acid ..#dd e6cess Cinc powder/granules.#dd a (50 cm ) of copper(BB) sulphate solution-.#t the same temperature

!6periment BB :

1. Dour /measure (051) cm of (.15 mol dm 5 ) hydrochloric acid .. #dd e6cess Cinc powder/granule. #t the same temperature

OR (Temperature)!6periment 1:

1. Dour /measure (051) cm of (.15 mol dm 5 ) hydrochloric acid. <eat acid to (5+ 7)=

. #dd e6cess Cinc powder/granule

!6periment BB :

1. Dour /measure (051) cm of (.15 mol dm 5 ) hydrochloric acid .. "ithout heating. #dd e6cess Cinc powder/granules

OR (7oncentration)!6periment 1:

1.Dour /measure (051) cm of (.5 mol dm 5 ) hydrochloric acid .. #dd e6cess Cinc powder/granules.#t the same temperature

1

1

1

1

1

1

1

1

1

1

1

1

1





!6periment BB :

1. Dour /measure (051) cm of (.151 mol dm 5 ) hydrochloric acid .. #dd e6cess Cinc powder/granules. #t the same temperature

OR

(AiCe)!6periment 1:1.Dour /measure (051) cm of (.15 mol dm 5 ) hydrochloric acid .. #dd e6cess Cinc powder .#t the same temperature

!6periment BB :

1. Dour /measure (051) cm of (.15 mol dm 5 ) hydrochloric acid .. #dd e6cess Cinc granule. #t the same temperature

1

1

1

1

1

1

1

1

(iv) (7atalyst)

1.7atalyst/copper(BB) sulphate is used in !6periment B. 7atalyst/(copper(BB) sulphate) lower activation energy (and provide an alternative path). More colliding particles / ions are able to achieve that lower activation energy.-.The fre4uency of effective collision between magnesium atoms and hydrogen ionincreases.0. The rate of reaction of !6periment B is higher.

(#ny -)(Temperature)

1. Eate of reaction in !6periment B is higher.. The temperature of reaction in !6periment B is higher

. The inetic energy of particles increases in !6periment B // The particles movefaster

-. re4uency of collision between magnesium atom and <$ ion in !6periment B ishigher

0. re4uency of effective collision in !6periment B is higher (#ny -)

(7oncentration)1. Eate of reaction in !6periment BB is higher . The concentration of acid in !6periment B is higher . The number of hydrogen ion per unit volume in !6periment BB is higher

-. re4uency of collision between magnesium atom and <$ ion in !6periment B ishigher

0. re4uency of effective collision in !6periment BB is higher (#ny -)

(AiCe)1.Eate of reaction in !6periment B is higher .The siCe of magnesium in !6periment B is smaller .Total surface area of magnesium in !6periment B is bigger/larger -.The fre4uency of collision between magnesium atoms and hydrogen ions in!6periment B higher 0.The fre4uency of effective collision between in !6periment B is higher (#ny -)

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

(v) The number of mol are same // The concentration and volume of acid are same 1





Ques!"#

N"

M$% s'(e)e M$%

/(a)(i)

1. irst minute * -/8 *.- cm s 51 // - cm min 51

. nd minute * -5-/8 *.182 cm s 51 // 1 cm min 511

1

(ii) . rate in 1 minute higher than st nd

minute (vice versa)-. concentration of sulphuric acid / mass of Cinc decreases 11

(iii) #ll hydrogen ion from acid was completely reacts 1

(iv) # catalyst lower activation energy provide an alternative pathMore colliding particles /Cinc atoms and hydrogen ions are able to overcome the lower activation energy.The fre4uency of ee'!7e '"44!s!"#s between Cinc atom and hydrogen ion in is higher.(any )

1

1

(b) 5 hydrogen and o6ygen molecules collide5 with correct orientation5total energy of particles higher or e4ual to activation /minimum energy

111

Te)*e%$u%e

M$e%!$4s:. mol dm5 sodium thiosulphate, 1. mol dm5 sulphuric acid, a piece of white paper D;F'<@ HJ ;" "Q< <&"F<

A**$%$us:10 cm conical flas, stopwatch, 0 cm measuring cylinder, 1 cm measuring

cylinder, thermometer, ?unsen burner, wire gauCe.

P%"'eu%e:

1.Fsing a measuring cylinder, 0 cm of . mol dm 5 sodium thiosulphate solution ismeasured and poured into a conical flas.

.The conical flas is placed on top of a piece of Q3"< A;A<F D;F'<@ HJ ;" "Q< <&"F<

.0 cm of 1. mol dm 5 sulphuric acid is measured using another measuring cylinder.

-.The sulphuric acid is poured immediately and carefully into the conical flas. #t thesame time, the stop watch is started

0.The mi6ture in a conical flas is swirled.

2Q< HJ D;F' 3I E!I<F<@ <F"3;==P BFED "Q< "EA EB "Q< E&3;= B=;I' "QFEXSQ "Q<solution.

2Q< I"EA;"Q 3I I"EAA<@ E&< "Q< HJ D;F' @3I;AA<;FI BFED 3<

+.Atep 1 2 are repeated using 0 cm of . mol dm 5 sodium thiosulphate solution at-o7, 0 7, 8 7 by heating the solution before 0 cm of sulphuric acid is added in.o o

M$;

C"#'4us!"#

"hen the temperature of sodium thiosulphate solution is higher , the rate of reaction ishigher

1

1

1

1

1

1

1

1

1

1

1





Te)*e%$u%e

M$e%!$4s:. mol dm5 sodium thiosulphate, 1. mol dm5 sulphuric acid, water, a piece of whiteA;A<F D;F'<@ HJ ;" "Q< <&"F<

A**$%$us:10 cm conical flas, stopwatch, 0 cm measuring cylinder, 1 cm measuring

cylinder, wire gauCe.

P%"'eu%e:

1.Fsing a measuring cylinder, 0 cm of . mol dm 5 sodium thiosulphate solution ismeasured and poured into a conical flas.

2Q< E&3;= B=;I' 3I A=;<@ E& "EA EB ; A3<< EB Q3"< A;A<F D;F'<@ HJ ;" "Q< <&"F<

.0 cm of 1. mol dm 5 sulphuric acid is measured using another measuring cylinder.

-.The sulphuric acid is poured immediately and carefully into the conical flas. #t thesame time, the stop watch is atarted

0.The mi6ture in a conical flas is swirled.

2Q< HJ D;F' 3I E!I<F<@ <F"3;=ly from the top of the conical flas through thesolution.

2Q< I"EA;"Q 3I I"EAA<@ E&< "Q< HJ D;F' @3I;AA<;FI BFED 3<

+.Atep 1 2 are repeated by adding 0 cm , 1 cm , 10 cm , cm and - cm of

distilled water .(at the same time) maintaining the total volume of solution at 0 cm

after dilution//table of dilutionM$;

C"#'4us!"#"hen the temperature of sodium thiosulphate solution is higher , the rate of reaction ishigher

1

1

1

1

1

1

1

1

1

1

1

SET 3 :THERMOCHEMISTR.

Ques!"#

N"

M$% s'(e)e M$%

1 (a) <eat change /released when 1 mol copper is displaced from copper (BB)sulphate solution by Cinc

1(b) ?lue to colourless

1(c) (i) 0 X -. X 8 S // 18 S

1(ii) (1. )(0)

1

1(iii) 18.0

1

// .0

S // 0 S mol51





* 5 0. S mol51 1

(d) 1. Correct reactant and product

. Correct two energy level for e8othermic reaction

. Correct value heat of displacement and unit

Aample answer

!nergy

111

(e) (i) W71

(ii) 'umber of mole copper displaced is half <eat released is half / 18

11

TOTAL 12


2 (a) <eat of precipitation is the heat change when one mole of a precipitate is

formed from its solution.

1

(b) To reduce heat loss to the surrounding.Eeect : prevent

1

(c) #g$ $ 7l : US>=5 1(d) (i) The heat released

*(0 $ 0) 6 -. 6 .0*1-2 S

1

(ii) 'umber of moles of #g$

* (0 6 .0) * .0 mol1

'umber of moles of 7l5

* (0 6 .0) * .0 mol1

1

1

(iii).0 mole of #g reacts with .0 mole of 7l to form .0 mole of $ 5

#g7l 'umber of moles of #g7l * .0 mol

1

(iv)* 5

44696 1-2 S

*0+ + S<eat of precipitation of #g7l * 50+.+ S mol51

1

1

(e)

(i)

#g$ $ 7l :US>=5 Y$ 50+.+Smol51

// #g'= 1;>= :US>= 1;1 Y$ 50+.+Smol511

S // 8 S

n $ 7uA= //n- $ 7u$

Y$ 5 0. Smol51

nA=- $ 7u //n$ $ 7u





(ii)

1. 3abel a6es. !nergy levels of reactants and products correct with formula of

reactants and products. <eat of precipitation written

11

1T"$4


. (a) (i) !thanol 1

(ii) 18 S of heat energy is released when one mole of ethanol is burntcompletely in e6cess o6ygen

1

(b)(i) 'o of moles of alcohol * . / -8

* .0 mol1 mol of alcohol burnt released 18 S

Thus, .0 mol of alcohol burnt released 8. S

1

1

(ii) mcθ * 8. S

mcθ * 8. 6 1θ* 8/ 6 -.

* 2.0 7

1

1

( c) <eat is lost to the surrounding // <eat is absorbed by the apparatus or containers // Bncomplete combustion of alcohol 1

(d) (i)

1. 3abel a6es

. !nergy levels of reactants and products correct with formula of reactantsand products. <eat of combustion written

11

1

7 < = < $ = 0

7= $ < =

Y $ 5 18 Smol51

#g $ 7l$ 5

Y$ 50+.+Smol

51

#g7l

!nergy

!nergy





(ii)

1. 3abel. unctional

11

(e) (i)5 808 Smol51 // 052 Smol51

1(ii) 1. The molecular siCe/number of carbon atom per molecule propanol is

bigger/higher methanol. 7ombustion of propanol produce more carbon dio6ide and water

molecules. More heat is released during formation of carbon dio6ide and water

molecules

1

1

1

T"$4 )$%s


+ (a) (i)7haracteristic ;iagram -.1 ;iagram -.7hange in

temperature

Bncrease ;ecrease

Type of chemicalreaction

!6othermic reaction !ndothermic reaction

!nergy contentof reactantsand products

The total energy content of the reactants )"%e ($#

the energy content of the products

The total energy content of the reactants 4ess ($# theenergy content of the

products

#mount of heat absorbed

/realeasedduring breaing of bonds

#mount of heat absorbedfor the breaing of bond in

the reactant is 4ess thanheat released duringformation of bond in the

products

#mount of heat absorbed for the breaing of bond in the

reactant is )"%e than heatreleased during formation of bond in the products

11

1$1

1$1

(ii) 'umber of moles of eA= * MI-

1* (.)(0) * .1 mol

1<eat change * .1 6 S

* S // S$ <;" Q;&S<D

(0)(-.) 7 o

1

1

1





(b) 1. 'umber of mole of #g ion in both e6periment$

* 0 6 .0 // .10 mol1

. 'umber of mole of 7l ion in both e6periment5

* 0 6 .0 // .10 mol1

. 'umber of mole of silver chloride formed is the same-. 'a ionand Q ion not involved in the reaction // #g ionand 7l involved in the$ $ $ 5

reaction

1

1

11

(c) (i) $ <;" Q;&S<D* (1)(-.)(-. .)* 0- S / 0.- S

'umber of moles of <7l / < $ ion * (0)( * .1 mol1

'umber of moles of 'a=< / =< ion * (0)() * .1 mol5

1The heat of neutraliCation * 0.-

.1Z$ 5 0.- S mol51

1

1

11

(ii) Temperature change is 1. 7 // sameo

'umber of moles of sodium hydro6ide reacted when hydrochloric acid or sulphuric acid is used is the same // .1 mol

'umber of mole of water formed when hydrochloric acid or sulphuric acid used

is the same // .1 mol< ion in e6cess when sulphuric acid is used$

1

1

11

T"$4 )$%s


0 (a) (i) 'eutralisation//!6othermic reaction 1

(ii) Total energy content of reactant is higher than total energy content in product

1

(iii) 1. The heat of neutraliCation of !6periment 1 is higher than !6periment

. <7l is strong acid while ethanoic acid is wea acid. <7l ionises completely in water to produce high concentration of < ion$

-. 7< 7==< ioniCes partially in water to produce low concentration of <$

ion and most of ethanoic acid e6ist as molecules0. Bn !6pt ,Aome of heat given out during neutraliCation reaction is used to

dissociate the ethanoic acid molecules completely in water//part of heatthat is released is used to brea the bonds in the molecules of ethanoicacid that has not been ionised

1

11

1

1

(b) (i) 'o of mol acid/alali* 0 X 1 /1* .0- Y $ &E EB DE=

* 02. X .0* .+80 S // +80 S

1

1

1(ii) +80 * 1 X -. X

[11





* 8.+ 7 ( correct unit)o 1

(iii) 1. Aome of heat is lost to the sorrounding. <eat is absorbed by polystyrene cup

11

(c ) # ?

The reaction is e6othermic// <eat isreleased to the surrounding during thereaction

The reaction is endothermic// <eatis absorbed from the surroundingduring the reaction

<eat released is 6 S when 1 mol product is formed

<eat absorbed is y S when 1 mol product is formed.

The total energy content in reactant ishigher than total energy content in

product

The total energy content inreactant is lower than total energycontent in product

The temperature increases during thereaction

The temperature decreases duringthe reaaction

<eat released during the formation of

bond in product is higher than heatabsorbed during the breaing of bondin reactant

<eat absorbed during the breaing

of bond in reactant is higher thanheat released during the formationof bond in product

1

1

1

1

1

T=T#3

8 (a) (i)

1. 5a6es : energy. Two different level of energy

11

(ii) 1. reactants have more energy // products have less energy.energy is released during the e6periment // this is e6othermic reaction

11

(b) 'o. of mol of < ion/=< * 160/1// .0$ 5

<eat change * 16 -. 62//9- Soule//.9- S<eat of neutraliCation* 59-/.0

* 50++ S mol 51//50+.+ S mol51

1111

(c) 1. <eat of combustion of propane is higher . The molecular siCe/number of carbon atom per molecule propane is

bigger/higher . Droduce more carbon dio6ide and water molecules//released more heat energy

111

1. Methanol/ethanol/ propanol,;iagram:

. 5labelled diagram. 5arrangement of apparatus is functional

1

11..

energy

n $ 7uA= -

nA=- $ 7u

Y$ 510 Smol51





1. (150 cm )of water is measured and poured into a copper can and the

copper can is placed on a tripod stand. the initial temperature of the water is measured and recorded. a spirit lamp with ethanol is weighed and its mass is recorded-. the lamp is then placed under the copper can and the wic of the lamp is lighted

up immediately

0. the water in the can is stirred continuously until the temperature of the water increases by about 7.o

8. the flame is put off and the (!6(es e)*e%$u%e reached by the water isrecorded

2. The lamp and its content is weighed and the mass is recordedR D;K

;ata

The highest temperature of water * t 6The initial temperature of water * t 1Bncrease in temperature, θ * t 6 5 t 1 * θ

Mass of lamp after burning * m6

Mass of lamp before burning * m1

Mass of lamp ethanol burnt, m * m1 5 m * m6 R

7alculation :

'umber of mole of ethanol, 7 < =<, n * 0 m RR

The heat energy given out during combustion by ethanol * the heat energy absorbed by water* 16 6 c 6 θ S<eat of combustion of ethanol * m c θ QS mol51

n* 5p S/mol R

..-

..

T"$4 )$%s






2 (a) (i) <eat change * mcθ * (0$0)(-.)(59) * --0 S

<eat of precipitation of #g7l* 5 --0 / .10 * 508 S mol51 // 0.8 S mol51

1. The position and name /formulae of reactants and products are correct.

. 3abel for the energy a6is and arrow for two levels are shown.

1

1

11(b) (i)

(ii)

1. <7l is a strong acid // 7< 7==< is a wea acid.

. <7l ionised completely in water to produce higher concentration of <$

ion. //. 7< 7==< ionised partially in water to produce lower concentration of

< ion.$

-. during neutralisation reaction, some of the heat released are absorbed by7< 7==< molecules to dissociate further in the molecules.

1. < A= is a diprotic acid// <7l is a monoprotic acid. -

. < A= produced two moles of hydrogen ion/< when one mole of the acid -$

ionised in water //. <7l produced one mole of hydrogen ion/ < when one mole of the acid$

ionised in water.-. "hen one mole of =< reacts with two moles of < will produce one5 $

mole of water, the heat of neutralisation is still the same as !6periment B because the definition of heat of neutralisation is based on the formationof one mole of water.

-Ma63

-Ma63

(c) 5 apparatus and material : mars5 procedures : 0 mars5 Table : 1 mar

5 7alculation : marsAample answer:#pparatus : Dolystyrene cup, thermometer, measuring cylinder.Materials : 7opper (BB) sulphate, 7uA= solution, Cinc powder.-

Drocedures :1. Measure 0 cm of . mol dm 5 copper (BB) sulphate, 7uA= solution and pour it-

into a polystyrene cup.. Dut the thermometer in the polystyrene cup and record the initial temperature of

the solution.. #dd half a spatula of Cinc powder 4uicly and carefully into the polystyrene cup.

-. Atir the reaction mi6ture with the thermometer to mi6 the reactants.0. Eecord the highest temperature reached.

11

1

11

11

!nergy

#g'= $ 'a7l

#g7l $ 'a'=\

∆< * 50.8 S mol51

\ #ccept ionic e4uation





SET + :CARBON COMPOUNDS


1 (a)

=r

1

(b) 7 < =< $ 9/= 2 Æ 7= $ -< = 1

(c) (i) Aweet/ pleasant smell /// fruity smell 1

(ii) Methanoic acid 1

(iii) 1$1

(d) (i) =6idation 1(ii) =range colour of acidified potassium dichromate (IB) solution turns green 1

(iii) 7 < =< $ K=L 2 Æ 7 < 7==< $ < = 0 1

(e) 7 < =< 2 Æ 7 < 8 $ < =

(ii)

1$1

Tabulation of data:

Bnitial temperature of 7uA= solution ( 7)-o

θ1

<ighest temperature of the reaction mi6ture ( 7)oθ

Temperature change ( 7)oθ 5 θ1

....1

7alculation : 'umber of mole of 7uA= -

* MI/1 * DE= RR

<eat change * mc(θ 5 θ1) * 6 S

<eat of displacement * 6 / .0 S mol51

* y S mol51 RR

T=T#3

*%"*e#e

*%"*$#"4

= < < <

< 7 = 7 7 7 <

< < <







2 (a) (i) ermentation 1(ii) !thanol 1

(iii)

1

(b) 7 < =< 0 $ = : > $ < = 1$1(c) (i) !thene 1

(ii)

1(d) Durple to colourless 1

(e) (i) !thyl ethanoate 1

(ii) 7< 7==< $ 7 < =< 0 Æ 7< 7==7 < 0 $ < = 1$1

Ques!"#

N"

M$% s'(e)e M$%

3 (a)C($%$'e%!s!'s E;*4$#$!"#

Aame general formula 7 <n n $ 1=<

successive member is different fromeach other by 7<

Eelative atomic mass is different by 1-

@radual change in physical properties //Melting / boiling point increase

'umber of carbon atom per molecules increase //siCe of molecule increase

Aimilar chemical properties //o6idation produce carbo6ylic acid

<ave same chemical/similar functional group

7an be prepared by similar method //can be prepared by hydration of

alene

<ave same chemical properties //have same functional group

1$1

1$1

1$1

1$1

1$1

(b) (i) (7< =)n * 8

(1 $ $ 18)n * 8n * 1

7 < = - 1

(ii) 7arbo6ylic acid 1

Eeact with carbonate to produce carbon dio6ide 1

=<

7

<

<7<

<

<

< <

৷ ৷

7 5 7

৷ ৷

< < n





(iii) 7< 7==< $ 7a7= : >$ 7==) 7a $ < = $ 7=

7orrect formula of reactants and products?alanced e4uation

11

(c)7ompound P Q

The number of carbon atom The number of hydrogen atom - 8

number of hydrogen atom & is higher

Type of covalent bond between // carbon/ Type of hydrocarbon

;ouble bond / /Fnsaturated

Aingle bond/ /Aaturated

Type of homologous series ////

'ame of compound

#lene//!thene //

#lane //!thane

@eneral formula//

Molecular formula of thecompound

7 <n n //

7 < -

7 <n n$ //

7 < 8

11

1

1

1

Ma6-


+ (a) (i) 1-. % 1

(ii) !lement 7 <Mass/ % +0.2 1-.

'o. of moles

1)

2.+0

* 2.1- 1

/.1-

* 1-.

Eatio of moles/Aimplest ratio 1-.2

1-.2 * 11-.2

/.1- *

!mpirical formula * 7<

EMM of (7< ) n * 08 .............1K(1 $ 1()Ln * 08

1-n * 08

n * 1-

08

* - RRRMolecular formula : 7 <- + RRRRRR

1

1

1

8 ma60

(iii)

Kany L

1$1

1$1

Ma6 -?ut515ene?ut55ene 5methylpropene





(iv) 7ompound M (?utene, 7 < ) has a higher percentage of carbon atom in their - +

molecule than butane, 7 <- 1 RRRRR

% of 7 in 7 <- + *+)1(-

)1(-

+

6 1%

*08

-+ 6 1%

% RRRR% of 7 in 7 < *- 1

1)1(-

)1(-

+

6 1%

*0+

-+ 6 1%

* +.2% RRR.....

(b) (i) AtarchDrotein / natural sil

11

(ii) < < 7< <B B B B

7 * 7 7 * 7B B< <

5methylbut51,5diene or isoprene

11..

(c) (i) Eubber that has been treated with sulphur 1(ii) Bn vulcanised rubber sulphur atoms form cross5lins between the rubber molecules

These prevent rubber molecules from sliding too much when stretched1

1T=T#3

Ques!"# N" M$% s'(e)e M$% (a) (i)

H?%"'$%"#T?*e "

"#H")"4"6"us

se%!ese#e%$4"%)u4$

A covalent alane 7 <n n$

B covalent alene 7 <n n

(ii) 7arbon dio6ide7 <- 1 $ 1= : > $ 1< =KChemical formulae of reactants and productsLK Balanced L

1

11

(iii) <ydrocarbon ?.<ydrocarbon ? is an unsaturated hydrocarbon which react with bromine.<ydrocarbon # is a saturated hydrocarbon which do not react with bromine.

1

1

1





(iv) <ydrocarbon ? more sootiness.? has higher percentage of carbon by mass.

% of carbon by mass

<ydrocarbon # : -(1) ] 1 // +.28 %

-(1) $ 1(1)

<ydrocarbon ? : -(1) ] 1 // +0.21 %-(1) $ +(1)

11

1

1

(b) 7arbo6ylic acid X :

Dropanoic acid

#lcohol :

!thanol

1

1

1

1

TOTAL


/ (a) (i) X 5 any acid methanoic acid 5 any alali ammonia a4ueous solution

11

(ii) 1. Methanoic acid contains hydrogen ions. <ydrogen ions neutralise the negative charges of protein membrane. Eubber particles collide,-. Drotein membrane breas0. Eubber polymers combine together

11111

0 ma6-

(iii) #mmonia a4ueous solution contains hydro6ide ions<ydro6ide ions neutralise hydrogen ions (acid) produced by activities of bacteria

1

1(b) (i) #lcohol 1

(ii) ?urns in o6ygen to form carbon dio6ide and water =6idised by o6idising agent (acidified potassium dichromate (IB) solution) toform carbo6ylic acid

11

(iii) Drocedure:1. Dlace glass wool in a boiling tube. Aoa the glass wool with cm of ethanol

. Dlace pieces of porous pot chips in the boiling tube-. <eat the porous pot chips strongly0. <eat glass wool gently





8. Fsing test tube collect the gas given off

;iagram:

Kunctional diagramLK3abeled porcelain chips, water, named alcohol, heatLTes:#dd a few drops of bromine water ?rown colour of bromine water decolourised

8 ma60

11

11

Total

Ques!"#N"

M$% s'(e)e M$%

(a) 7arbon dio6ide/ 7= and water/ < =

,ny one correct chemical equation

38ample

7 <- 1 $ 1= : > $ 1< =Chemical formula of reactants

Balanced

1

11

(b) 7ompound ? > 7ompound ;Aame molecular formula / 7 <- +

;ifferent structural formula

111

(c) Dour compound #/? into a test tube#dd bromine water to the test tube and shaeTest tube contain compound # unchangedTest tube contain compound ? brown colour turn colourless

or

Dour compound #/? into a test tube#dd acidified Dotassium manganate(IBB) s"4u!"# to the test tube and shae

Test tube contain compound # unchangedTest tube contain compound ? purple colour turn colourless

1111

(d)(i)

,ny members of carbo8ylic acid and correct ester

38ample

KMethanoic acidLKDropylmethanoateL

11

1

1

<eat <eat

@lass woolsoaed with

ethanol

P"%'e4$!# '(!*s

"ater





(d)(ii)

Dour cm of Kmethanoic acidL into a boiling tube

#dd cm of propanol/compound ! into the boiling tube

S4">4?5'$%eu44?5%"* 1 cm of concentrated sulphuric acid

<eat the mi6ture gentlyDour the mi6ture in a beaer that contain water Observation : 7olorless li4uid with fruity smell is formed / 7olorless li4uid float onwater surface

111111

TOTAL 20

Ques!"#N"

M$% s'(e)e M$%

+(a)

?ut55ene

5methylpropene

1$1

1$1

(b) (i)

(ii)

Dropanoic acid!thanol

7hemical properties for propanoic acid:1. Eeact with reactive metal to produce salt and hydrogen gas. Eeact with bases/alali to produce salt and water . Eeact with carbonates metal to produce salt, carbon dio6ide gas and water -. Eeact with alcohol to produce ester

Kany threeL

7hemical properties for ethanol:1. Fndergo combustion to produce carbon dio6ide and water . ?urnt in e6cess o6ygen to produce 7= and < =

. Fndergo o6idation to produce carbo6ylic acid / ethanoic acid-. Eeact with acidified Q 7r = /QMn= to produce carbo6ylic acid / ethanoic acid 2 -

0. Fndergo dehydration to produce alene / ethene.K#ny three answersL

11

11111

1111

1

(c) (i) D : <e6ane& : <e6ene // <e6515ene

(ii) Eeaction with bromine // acidified potassium manganate(IBB) solution

Drocedure:

11

1

1

C C C CH

H H H H

H

H H

C

C C C

H

H

H

H

H

H

H

H





1. Dour about K 50 cm L of D into a test tube.

. #dd -50 drops of bromine water / acidified potassium manganate(IBB) solutionand shae.

. =bserve and record any changes.-. Eepeat steps 1 to by replacing D with &

=bservation:D : ?rown/ Durple colour remains unchanged.& : ?rown/ Durple colours decolourise / turn colourless.

1

11

11

Ma6 8

20

SET + :MANUFACTURED SUBSTANCE IN INDUSTR.


1 (a) (i) 7ontact process 1

(ii) #mmonia 1

(iii) Ianadium(I) o6ide, -0 7 5 0 7o o 1

(iv) #mmonium sulphate 1

(v) '< $ < A= - Æ ('< ) A=- - 1$1(b) (i) 7omposite material

1

(ii) 7orrect arrangement7orrect label

11

(iii) n7 < 7l Æ 55( 7 < 7l ) n 1

(iv) Bt has low thermal e6pansion coefficient // resistant to thermal shoc 1

T=T#3 11


2 (a) (i)

(ii)

A= $ < = Æ < A=

• 7orrodes buildings• 7orrodes metal structures• p< of the soil decreases• 3aes and rivers become acidic

K#ble to state any three items correctlyL

1

-

Tin atom

7opper atom






(b) (i)

(ii)(iii)

• =leum• A= $ = Æ A=

• Moles of sulphur * -+ / *1.0• Moles of A= * moles of sulphur

* 1.0• Iolume of A= * 1.0 × - dm

* 8 dm

111

11

1 8

(c) (i) • Dure metal are made up of same type of atoms and are of the same siCe.• The atoms are arranged in an orderly manner.• The layer of atoms can slide over each other.• Thus, pure copper are ductile.

• There are empty spaces in between the atoms.• "hen a pure copper is noced, atoms slide.• Thus, pure copper are malleable.

1

11

111

1Ma6:0(ii) • inc.

• inc atoms are of different siCe,• The presence of Cinc atoms !s%u* the orderly arrangement of copper

atoms.• This reduce the layer of atoms from sliding.

#rrangement of atoms 1 3abel 5 1

111

1

1

1Ma6:

T"$4 20


3 (a) • <aber process• Bron• ' $ < '<

11

1$1

(b) Dure copper ?ronCe

?ronCe is harder than pure copper

• Tin atoms are of different siCe

• The presence of tin atoms distrupt the orderly arrangement of copper

1

1$1

1

1

Zinc atom

Copper atom

Tin atom

Copper atom





atoms.

• This reduce the layer of atoms from sliding. 1

1M#X

8

Procedure71. Bron nail and steel nail are cleaned using sandpaper.. Bron nail is placed into test tube # and steel nail is placed into test tube

?.. Dour the agar5agar solution mi6ed with *"$ss!u)

(e;$'?$#"e%%$eIII solution into test tubes # and ? until it coversthe nails.

-. 3eave for 1 day.0. ?oth test tubes are observed to determine whether there is any blue

spots formed or if there are any changes on the nails.8. The observations are recorded

9esults7

Tes ue T(e !#e#s!? " 4ue s*"s

# <igh? 3ow

Conclusion7

Bron rust faster than steel.

11$ 1

1

11

11

1

T=T#3

SET + :CHEMICALS FOR CONSUMERS


1 (a) (i) To improve the colour of food 1

(ii) #bsorbs water /inhibits the growth of microorganisms 1

(iii) 1. Dreservative. lavouring

11

(b) (i) #nalgesic 1

(ii) To relieve pain 1

(c) (i) Aaponification // alaline hydrolysis 1

(ii)

<ydrophobic hydrophilic

1$1

(iii) Aoap form scum/insoluble salts in hard water. 1

T=T#3 1






2 (a) !6amples of food preservatives and their functions:• Aodium nitrite slow down the growth of microorganisms in meat• Iinegar provide an acidic condition that inhibits the growth of

microorganisms in picled foods

1$1

1$1

(b) (i) 'o // cannot

?ecause aspirin can cause brain and liver damage if given to children withflu or chicen po6. // Bt causes internal bleeding and ulceration

1

1

(ii) Daracetamol7odeine

11

(iii) 1. Bf the child is given a overdose of codeine, it may lead to addition.2. Bf the child is given paracetamol on a regular basis for a long time, it

may cause sin rashes/ blood disorders /acute inflammation of the pancreas.

1

1

(c)T?*e " ""

$!!7es

E;$)*4es Fu#'!"#

Dreservatives Augar, salt To slow down the growthof microorganisms

lavourings Monosodiumglutamate, spice,garlic

To improve and enhancethe taste of food

#ntio6idants #scorbic acid To prevent o6idation of food

;yes/ 7olourings TartraCineTurmeric

To add or restore thecolour in food

;isadvantages of $#? >" food additives:Augar eating too much can cause obesity, tooth decay and diabetesAalt may cause high blood pressure, heart attac and stroe.TartraCine can worsen the condition of asthma patients

- May cause children to be hyperactiveMA@ can cause difficult in breathing, headaches and vomiting.

11

T=T#3


3 (a) (i) • Traditional medicines are derived from plants or animals.• Modern medicines are made by scientists in laboratory and based on

substances found in nature.

11

(ii)Type Modern medicine

#nalgesics#spirinDaracetamol7odein

#ntibiotics DenicillinDsychotherapeutic 7hloropromaCin

7affeina

111

1

11

M#X0

(iii) Pe#!'!44!#7ause allergic reaction, diarrhoea, difficulty breathing and easily bruising 1





C"e!#e7ause addiction, drowsiness, trouble sleeping, irregular heartbeat andhallucinations.

As*!%!#

7ause brain and liver damage if given to children with flu or chicen po6.7ause internal bleeding and ulceration

1

1

(b) <ard water contains '$4'!u) !"#s and )$6#es!u) !"#s.!6ample : sea water

P%"'eu%e

1. cm of hard water (magnesium sulphate solution) is poured into two

separate beaers X and .. 0 cm of soap and detergent solutions are added separately in beaer X

and beaer .. # small piece of cloth with oily stains is dipped into each beaer.-. !ach cloth is washed.0. The cleansing action of the soap and detergent is observed.

Resu4s

Be$e% Ose%7$!"#

X The cloth is still dirty.

The cloth becomes clean.

C"#'4us!"#The cleansing action of detergent is more effective than soap in hard water

1

1

1

1

111

11

1





SET :PAPER 3 SET 1

Eubric Acore1(a)(i) ,ble to give correct observation

Aample answer:7olourless solution formed//#luminium o6ide powder dissolved in nitricacid/sodium hydro6ide solution.

Eubric Acore1(a)(ii) ,ble to give the correct inference(

Aample answer #luminium o6ide is soluble in nitric acid/sodium hydro6ide

solution//#luminium o6ide shows basic/acidic properties

Eubric Acore1(a) (iii) ,ble to give the correct property of aluminium o8ide(

#nswer: amphoteric

Eubric Acore1(b) ,ble to state the hypothesis correctly(

Aample answer:"hen aluminium o6ide dissolves in nitric acid, it shows basic properties,when aluminium o6ide dissolves in sodium hydro6ide solution, showsacidic properties.

Eubric Acore1(c) ,ble to state all the variables correctly.

#nswer:

Manipulated variable: type of solutions // nitric acid and sodiumhydro6ide solutionEesponding variable: solubility of aluminium o6ide in acid andalali//property of aluminium o6idei6ed variable: aluminium o6ide

Eubric Acore1(d) ,ble to state the operational definition correctly(

Aample answer."hen aluminium o6ide solid is added into sodium hydro6ide solution, thesolid dissolved.






Eubric Acore1(e)(i) ,ble to give the correct observations for both e8periments(

Eed litmus paper turns blue?lue litmus paper turns red

Eubric Acore

1(e)(ii) ,ble to classify all the o8ides correctly(#cidic o6ide ?asic a6ide7arbon dio6ideDhosphorous pento6ide

Magnesium o6ide7alcium o6ide

Eubric Acore(a) ,ble to state the observation

Aample #nswer: 1. Bron glowed brightly. Bron ignited rapidly with bright flame.

. Bron glowed dimly

Eubric Acore(b) #ble to state the observation and the way on how to control variable

Aample #nswer : 1. change bromine with chlorine and iodine. Bgnition or glowing of halogen. Fse the same 4uantity of iron wool in each

e6periment.

Eubric Acore(c) ,ble to state the correct hypothesis by relating the manipulated variable

and responding variable

Aample #nswer :1. The higher the position of halogen in group 12 the

higher the reactivity towards iron.. The higher the position of halogen in group 12 the greater the ignition

or glowing reaction with iron.

Eubric Acore

(d) ,ble to state the inference correctly(

Aample answer:The solid of Bron(lll) bromide formed//?romine combined with iron //Bronis o6idiCed by bromine//?romine is reduced by iron

Eubric Acore(e) ,ble to arrange the three position of halogen based on the reactivity

toward iron in ascending order

#nswer : Bodine. ?romine, 7hlorine,

Eubric Acore(a) ,ble to give the correct arrangement of the metals

#nswer: Magnesium, , copper





Eubric Acore(b) ,ble to give the name of metal : correctly.

#nswer: inc//Bron//3ead

Eubric Acore

(c) ,ble to give the three observations correctly(

#nswer:1. ?rown solid deposited. ?lue solution turns light blue. inc strip becomes pale blue.

Eubric Acore

-(a) ,ble to give the problem statement correctly(

Aample answer:

<ow is the effect of other metals on the rusting of iron when the metalsare in contact with iron.

Eubric Acore-(b) ,ble to state the three variables correctly(

#nswer:Manipulated variable: Type of metals//inc and copper Eesponding variable: Eusting of ironi6ed variable: iron nail

Eubric Acore-(c) ,ble to state the hypothesis correctly(

Aample answer:"hen iron is in contact with a more electropositive metal/Cinc, rustingwill not occur, when iron is in contact with less electropositivemetal/copper, rusting will occur.

Eubric Acore-(d) ,ble to list the apparatus and materials needed for the e8periment(

#pparatus: two test tubes, test5tube rac,

Materials: hot agar5agar solution added with phenolphthalein and potassium he6acyanoferrate(BBB) solution, iron nails, Cinc strip, copper strip, sand paper.

Eubric Acore-(e) ,ble to give the procedures correctly

Aample answer:1. 7lean pieces of iron nails, Cinc strip and copper strip with sand

paper.. 7oil the iron nails with Cinc strip and copper strip each.. Dut the iron nails into two different test tubes-. Dour hot agar into each test tube until the iron nail is immersed.0. 3eave the apparatus for about 1 day and record the observations.





Eubric Acore-(f) ,ble to tabulate the data correctly

#nswer:!6periment =bservationBron nail coiled with Cinc

Bron nail coiled with copper

6

PAPER 3 SET 2

Eubric Acore1(a) ,ble to construct the table correctly with the following aspects:

!6periment #mmeter reading/#B .

BB .0BBB .

Eubric Acore1(b) ,ble to state the inference correctly.

Aample answer:3ead(BB) bromide can conduct electricity in molten state//'aphthalene/@lucosecannot conduct electricity in molten state

Eubric Acore1(c) ,ble to state the type of compound correctly

#nswer: ionic compound

Eubric Acore1(d) ,ble to state all the three variables correctly7

#nswer:Manipulated variable: type of compoundEesponding variable: ammeter reading//conductivity of electricity

i6ed variable: state of compound//ammeter

Eubric Acore1(e) ,ble to state the hypothesis correctly(

Aample answer:Molten ionic compound can conduct electricity but molten covalent compoundcannot conduct electricity.

Eubric Acore1(f) ,ble to state the operational definition correctly(

Aample answer:"hen carbon electrodes are dipped into molten lead(BB) bromide, ammeter shows a reading/ammeter needle deflects






Eubric Acore1(g) ,ble to e8plain the difference in conductivity of electricity in 38periment * and

**(Aample answer:Bn !6periment BB, molten lead(BB) bromide consists of free moving ions that

carry the electrical current, Bn !6periment B molten naphthalene consists of neutral molecules.

Eubric Acore1(h) ,ble to classify the substances correctly(

#nswer:Aubstance can conduct electricity Aubstance cannot conduct electricity7arbon rod7opper(BB) sulphate solution

@lacial ethanoic acidMolten polyvinyl chloride

Eubric Acore(a) ,ble to give the correct value of the reading(

#nswer: inal burette reading * -. cm

Bnitial burette reading * -2. cm

X * 0. cm

Eubric Acore(b) ,ble to draw the correct graph with the following aspects(

1. X a6is and y5a6is with label and unit

. 7orrect scale. 7orrect shape of graph

Eubric Acore(c) ,ble to determine the correct mole ratio(

#nswer:#g$ : 7l 5

1. 6 0 : 1. 6 01 1.0 : .0

1 : 1

Eubric Acore(d) ,ble to write the ionic equation correctly(

#nswer: #g$ $ 7l : US>=5

Eubric Acore(e) ,ble to s$etch the correct curve7

@raph constant at I * 1 cm

Eubric Acore





(f) ,ble to classify the salts correctly(

Aoluble salt Bnsoluble saltDotassium chloride

'icel nitrate#mmonium carbonate

?arium sulphate

Eubric Acore. (a) ,ble to state the problem statement correctly(

Aample answer:"hat is the effect of siCe of Cinc on the rate of reaction with sulphuric acid^

Eubric Acore(b) ,ble to state the hypothesis correctly

Aample answer:"hen siCe of Cinc is smaller, the rate of reaction is higher.

Eubric Acore(c) ,ble to state the all the variables correctly

#nswer:Manipulated variable: big siCed granulated Cinc and small siCed granulated CincEesponding variable: rate of reactioni6ed variable: volume and concentration of sulphuric acid

Eubric Acore(d) ,ble to list the necessary materials and apparatus needed(

Aample answer:Materials: big siCed granulated Cinc, small siCed granulated Cinc, .1 mol dm5

sulphuric acid, water.#pparatus: burette, conical flas, delivery tube with stopper, basin, retort,

basin, weighing balance, stop watch, measuring cylinder.

Eubric Acore(e) ,ble to list procedures for the e8periment

Aample answer.1. K051L g of big siCed granulated Cinc is weighed and put into the

conical flas.. <alf filled a basin with water.. ill burette with water and invert into the basin and record the initial

reading.-. Measure 0 cm of sulphuric acid and pour into the conical flas.

0. Atopper the conical flas and immediately start the stop watch.

8. Eecord the burette reading every s intervals for 0 minutes.2. Eepeat the e6periment by replacing the big siCed granulated Cinc with

small siCed granulated Cinc.





Eubric Acore(f) ,ble to tabulate the data with the following aspects7

Time/s 8 9 1 10 1+ 1?urettereading/cm

Iolume of gas/cm

PAPER 3 SET 3

EF?EB7 A7=E!1(a) ,ble to record all the temperature accurately

Aample answer :

!6periment 1

Bnitial temperature * +.<ighest temperature * -.7hange of temperature * 1.

!6periment BB

Bnitial temperature * +.<ighest temperature * +.7hange of temperature * 1.

EF?EB7 A7=E!1(b) ,ble to construct table accurately with correct title and unit

Aample answer :

Temperature !6periment B !6periment BBBnitial temperature of mi6ture, 7o +. +.<ighest temperature of mi6ture, 7o -. +.

7hange of temperature, 7o 1. 1.

EF?EB7 A7=E!1(c) ,ble to state the relationship between manipulated variable and responding variable

with direction correctly

Aample answer :

Manipulated variable : type of acid

Eesponding variable : heat of neutralisation;irection : ^

The reaction between a strong acid and strong alali produce a greater heat of





neutraliCation than the reaction between a wea acid and strong alali.//The reaction between hydrochloric acid and sodium hydro6ide produce a greater heat of neutraliCation than the reaction between ethanoic acid and sodium hydro6ide//The heat of neutraliCation between a strong acid and a strong alali is greater than theheat of neutraliCation between a wea acid and a strong alali

EF?EB7 A7=E!1(d) ,ble to e8plain with two correct reasons

Aample answer :

• This is to enable the change in temperature to be measured.• The change of temperature is needed to calculate the heat of neutraliCation

EF?EB7 A7=E!

1(e) ,ble to state the formula accurately

Aample answer :

7hange in temperature * <ighest temperature of mi6ture 5 initial temperature of mi6ture

EF?EB7 A7=E!1(f) ,ble to state three observation correctly

Aample answer :1. # colourless mi6ture of solution is obtained. The vinegar smell of ethanoic acid disappears. The polystyrene cup becomes warmer

EF?EB7 A7=E!1(g) ,ble to state three constant variables correctly

Aample answer :

1. The volumes and concentration of the acid and the alali. The type of cup used in the e6periment. The type of alali

EF?EB7 A7=E!1(h) ,ble to calculate the heat of neutralisation for e8periment * and ** correctly

Aample answer :

!6periment B

$<;" F<=<;I<@D_* 0 6 -. 6 1* 0 S





'umber of mole of sodium hydro6ide * MI* . 6 0/1* .0 mol

.0 mole of sodium hydro6ide releases 0 S heat energy

1. mole of sodium hydro6ide releases * heat released / number of mole* 0 / .0* 0- S

<eat of neutralisation * 5 0.- S/mol

!6periment BB

$<;" F<=<;I<@D_* 0 6 -. 6 1* 1 S

'umber of mole of sodium hydro6ide * MI* . 6 0/1* .0 mol

.0 mole of sodium hydro6ide releases 1 S heat energy

1. mole of sodium hydro6ide releases * heat released / number of mole* 1 / .0* - S

<eat of neutralisation * 5 -. S/mol

EF?EB7 A7=E!1(i)

,ble to write the operational definition for the heat of neutralisation correctly( ,ble to

describe the following criteria

(i) "hat should be done(ii) "hat should be observed

Aample answer :

The heat of neutraliCation is defined as the temperature rises when one mole of water is produced from reaction between acid and alali

EF?EB7 A7=E!1() ,ble to state the relationship between type of acid and value of heat of neutraliation and

e8plain the difference correctly(

Aample answer :

1. The heat of neutraliCation of a wea acid by a strong alali is less than the heat of neutraliCation of a strong acid by a strong alali.

!6planation :





. !6periment B uses a strong acid whereas !6periment BB uses a wea acid.. ;uring neutraliCation of a wea acid such as ethanoic acid, small portion of the heat

released in e6periment BB is absorbed to help the dissociation of the ethanoic acidmolecules

EF?EB7 A7=E!1() ,ble to predict the temperature change accurately

Aample answer :

3ower than 1 7o

EF?EB7 A7=E!1(l) ,ble to classify the acids as strong acid or wea$ acid(

Aample answer :

'ame of acid <eat of neutraliCation /Smol51 Type of acid

!thanoic acid 5 0. "ea acid

<ydrochloric acid 5 02. Atrong acid

Methanoic acid 5 0.0 "ea acid

EF?EB7 A7=E!

(a) ,ble to record all the temperature accurately one decimal places(

#ime <<(= s at >= C o

#ime 5?(= s at >< C o

#ime 56(= s at 5= C o

#ime >@(= s at 5< C o

#ime >>(= s at <= C o

EF?EB7 A7=E!(b) ,ble to construct table accurately with correct title and unit

Aample answer :

#emperature& C o

>= >< 5= 5< <=

#ime&s <<(= 5?(= 56(= >@(= >>(=

1&time & s21

=(=1? =(=61 =(=65 =(=6@ =(=>=

EF?EB7 A7=E!(c)(i) ,ble to draw the graph of temperature against 1&time correctly

i) #6is 6 : temperature / 7 and a6is y : 1/time /1/s

ii) 7onsistent scale and the graph half of graph paper iii) #ll the points are transferred correctlyiv) 7orrect curve





EF?EB7 A7=E!(c)(ii) state the relationship between the rate of reaction and temperature correctly

The rate of reaction increases with the increase in temperature

EF?EB7 A7=E!(d)

,ble to predict the time ta$en

!rom the graph/ when temperature A << C/o

1&time A =(=>> s21

#ime A 1&=(=>>

A >=(> s

EF?EB7 A7=E!

(e)(i) #ble to state all variables correctly

Manipulated variable : Temperature of sodium thiosulphate solutionEesponding variable : Eate of reaction between sodium thiosulphate and hydrochloric

acid//time taen for the sign X disappear 7onstant variable : 7oncentration and volume of sodium thiosulphate solution and

hydrochloric acid

EF?EB7 A7=E!(e)(ii) ,ble to state how to manipulate one variable while $eeping the other variables

constant(

Temperature is the manipulated variable.<eating sodium thiosulphate with several different temperatures by remaining the





concentration and volume of sodium thiosulphate and hydrochloric acid constant helpsmaintain the responding variable.

EF?EB7 A7=E!(f) ,ble to give the hypothesis accurately

Manipulated variable : Temperature of sodium thiosulphate solutionEesponding variable : Eate of reaction between sodium thiosulphate and hydrochloric

acid//time taen for the sign X disappear

The higher the temperature, the higher the rate of reaction is

EF?EB7 A7=E!(g) ,ble to state the relationship between temperature and the rate reaction in our daily

lives correctly

The lower the temperature, the lower the rate of food turns bad

EF?EB7 A7=E!(a) ,ble to -ar$e a statement of the problem accurately and must be in question form

;oes concentration of ions affect the product of electrolysis process at the anode^

EF?EB7 A7=E!

(b) ,ble to state the relationship between manipulated variable and responding variablecorrectly

The higher the concentration of ions at the $#"e, the higher its tendency to bedischarge.

EF?EB7 A7=E!(c) ,ble to state all the three variables correctly

Manipulated variables : concentration of sodium chloride solution

Eesponding variables : product formed at anode7ontrolled variables : 4uantity of current, carbon electrodes

EF?EB7 A7=E!(d) ,ble to state the list of substances and apparatus correctly and completely

Materials : .1 mol dm5 sodium chloride solution, . mol dm5 sodium chloridesolution.

#pparatus : carbon electrode, electrolytic cell, test tubes, dry cell, blue litmus paper,wooden splinter, ?unsen burner.





EF?EB7 A7=E!(e) ,ble to state a complete e8perimental procedure

1. ill electrolytic cell with .1 mol dm 5 sodium chloride solution.. 7onnect carbon electrodes to the power supply and ammeter.. Awitch on the circuit for half hour.-. 7ollect the gas at the anode and test with a glowing wooden splinter and a damp

blue litmus paper.0. Eepeat the step 1 to - by replacing .1 mol dm5 sodium chloride solution with

. mol dm5 sodium chloride solution.

EF?EB7 A7=E!(f) ,ble to draw a suitable table with title correctly

Aolution =bservation Droduct formed atanode

.1 mol dm5sodiumchloride solution. mol dm5sodiumchloride solution

EF?EB7 A7=E!- (a) ,ble to give the statement of problem correctly(

Aample answer:

;oes the type of electrode/anode affect the choice of ions to be discharged^

EF?EB7 A7=E!- (b) ,ble to state all variables correctly

Aample answer:

Manipulated variable : Type of electrode/ anodeEesponding variable : Droduct formed at anode7ontrolled variable : !lectrolyte

EF?EB7 A7=E!-(c) ,ble to give the hypothesis accurately

Aample answer:

Type of electrode/anode will influence the choice of ion to be discharged// type of electrode/anode will produce different product.

EF?EB7 A7=E!

-(d) ,ble to list completely the materials and apparatus(

Aample answer:Materials:





1. copper(BB) sulphate solution, (.0 .) mol dm5 //any suitable solution thatmatch with metal plate used.

. carbon rod. copper plate// any metal plate that match with a solution used.-. wooden splinter// any suitable material used for

testing a gas or any product at anode.

#pparatus:1. electrolytic cell. battery. connecting wire-. test tube

EF?EB7 A7=E!-(e) #ble to state all procedures completely and correctly.

Aample answer:

1. ill the electrolytic cell (beaer) with half full of copper (BB) sulpahate solution(any suitable electrolyte that match with metal plate used).. # test tube filled with copper (BB) solution is inverted on the $#"e '$%"#

electrode.. 7omplete the circuit.-. !lectricity is flowed.0. Eecord observation at anode..8. Atep 150 is repeated using copper plate

EF?EB7 A7=E!

-(f) ,ble to e8hibit the tabulation of data correctly(

Aample answer:

Type of electrode =bservation7arbon7opper/any metal

PAPER 3 SET +

Eubric Acore

1(a) ,ble to state all the observations and inferences correctly

Aample answers:

=bservations Bnferences

1. inc electrode become thinner inc atom ionised to Cinc ions//Cinc atomionises

. ?rown deposite is formed atcopper electrode//thicer

7opper atom is formed

. ?lue solution turn tocolourless/ become paler //

The intensity of blue solutiondecrease

7opper(BB) ions is discharged to copper atom//concentration of copper(BB) iondecreases

8

Eubric Acore





1(b) ,ble to state all the voltmeter readings accurately with unit

Aample answer:

inc and copper : 1.- ID and copper : .+ I

& and copper : .+ IE and copper : .- I

Eubric Acore1(c) ,ble to construct a table to record the voltmeter reading for each pair of metals

accurately

Aample answer:

Dairs of metals Ioltage / Iinc and copper 1.-

D and copper .+& and copper .+E and copper .-

Eubric Acore1(d) ,ble to arrange all the metals in ascending order in electrochemical series

Aample answer:7opper, E, D, inc, &

Eubric Acore1(e) ,ble to state the relationship between the manipulated variable and the responding

variable with direction(

Aample answer:The further the distance between two/pair of metals in the electrochemical series thehigher/larger/bigger the voltage value.

Eubric Acore1(f) ,ble to state all the three variables correctly

Aample answer:Manipulated variable : Dairs of metalsEesponding variable :Ioltmeterreading/voltage/potential difference7onstant variable : copper electrode, copper(BB) sulphate solution

Eubric Acore1(g) ,ble to state the operational definition for the potential difference accurately

Aample answer:The potential difference is the voltmeter reading when two different metals are dipped

in an electrolyte.





Eubric Acore1(h) ,ble to classify the cations and anions in copper)**+sulphate solution correctly

Aample answer:

7ations 7u , <$ $

anions A=-5, =<5

Eubric Acore1(i) ,ble to predict the positive terminal and the voltage value correctly

Aample answer:

Dositive terminal Ioltage /ID .

Eubric Acore1(i) ,ble to e8plain the relationship between the time for negative terminal to corrode and

the position in electrochemical series accurately

Aample answer:The distance between magnesium and copper in electrochemical series further//thedistance between Cinc and copper in electrochemical series is closer

Eubric Acore

(a) ,ble to state the inference correctly(

Aample answer:The reactivity (of alali metals with o6ygen) increase from lithium to potassium. //3ithium, sodium and potassium / alali metals show similar chemical in their reactionswith o6ygen.

Eubric Acore (b) ,ble to state the three variables correctly7

1( -ethod to manipulate variable(

6( #he responding variable(. #he controlled variable.

Aample answer:(i) Fse different types of (alali) / (group 1) metals(ii) Eeactivity of metals with o6ygen // Iigorousness of the reaction between

metals and o6ygen.(iii) =6ygen gas // siCe / mass of metal

Eubric Acore1 (c) ,ble to state the relationship correctly between the manipulated variable and the

responding variable(

Aample answer:(The lower/higher the position of metal in)/(@oing down/up) @roup 1, the more/less





reactive is the metal in reaction with o6ygen. //The lower/higher the metal in @roup 1 the more/less reactive the reaction witho6ygen.

Eubric Acore

(d) ,ble to give the operational definition accurately by stating the following threeinformation(

5 al$ali metals

5 vigorously & more vigorous & reactive with o8ygen

5 more & highly reactive

Aample answer:#n alali metal that reacts more vigorously with o6ygen is a more reactive metal.

Eubric Acore (e)(i) ,ble to state the position of metal in 4roup 1 accurately(

Aample answer:Deriod 0/8/2

Eubric Acore (e)(ii) ,ble to arrange the metals in ascending order based on their reactivity(

Aample answer:3ithium, Aodium, Dotassium, X // 3i, 'a, Q, X

Eubric Acore (f) ,ble to state the relationship between the mass of sodium and the time ta$en for the

metal to burn completely in o8ygen gas(

5 the higher the mass & the bigger the sie

5 the longer the time ta$en

5 burn completely

Aample answer:The higher the mass of metals, the longer the time taen to burn completely. //The bigger the siCe of metals, the longer the time taen to burn completely.

Eubric Acore (g) ,ble to record all the readings with one decimal place accurately(

Aample answer:

1.1 , 1.8, 1.9





Eubric Acore (h) ,ble to state observations for blue and red litmus paper correctly(

Aample answer:

Aolutions Eed litmus paper ?lue litmus paper

@as Sar B Turns blue 'o change@as Sar BB Turns blue 'o change@as Sar BBB Turns blue 'o change

Eubric Acore (i) ,ble to write the two balanced chemical equations for the reaction accurately(

Aample answer :i. -'a $ = Æ 'a = andii. 'a = $ < = Æ 'a=<

'otes: Aodium can be replaced with any alali metals from Table 1.

Eubric Acore () ,ble to classify all al$aline solutions into strong al$ali and one wea$ al$ali

correctly(

Aample answer:Atrong alali : Aodium hydro6ide / 'a=<,

Dotassium hydro6ide / Q=<7alcium hydro6ide / 7a(=<)

"ea alali : #mmonia solution/ '<

Eubric Acore(a) ,ble to give the statement of the problem accurately( 9esponse is in question form(

Aample answer:;oes the temperature of sodium thiosulphate solution affect the rate of reaction

between sodium thiosulphate solution and sulphuric acid^ //<ow does the temperature of sodium thiosulphate solution affect the rate of reaction^ between sodium thiosulphate solution and sulphuric acid^

Eubric Acore (b) ,ble to state the three variables correctly

Aample answer:

Manipulated variable: Temperature of sodium thiosulphate solution0 <IAE&@3&S ;F3;!=< 0;"< EB F<;"3E& 23D< ";'<& BEF D;F' HJ "E !<ED<

invisible /disappear 7onstant variable: Iolume and concentration of sodium thiosulphate/ sulphuric acid/ siCe of conical flas

Eubric Acore (c) ,ble to state the relationship correctly between the manipulated variable and the

responding variable with direction(

Aample answer:





The higher/lower the temperature of sodium thiosulphate solution, the higher/lower the rate of reaction. //The higher/lower the temperature of sodium thiosulphate solution, theIQEF"<F=E&S<F "Q< "3D< ";'<& BEF D;F' HJ "E @3I;AA<;F BFED I3SQ"3<

Eubric Acore(d) #ble to give complete list of materials and apparatus

Aample answer:Materials : Aodium thiosulphate solution, sulphuric acid.#pparatus : 7onical flas, ,bunsen burner, measuring cylinder, stop5watch,

filter paper.

Eubric Acore(e) ,ble to list all the steps correctly

Aample #nswer:

1. H HD;F' 3I @F;& E& ; A3<< EB Q3"<B3="<F ;F@!E;F@ A;A<F. 0 cm of sodium thiosuphate solution K(.151.) mol dm L is 5

measured with a measuring cylinder and is poured into a conical flas.. The solution is slowly heated until 7.o

-. 0 cm of hydrochloric acid K(.15 .) mol dm L is measured with a 5

measuring cylinder and is added to the conical flas. # stop5watch is

started immediately.0. The conical flas is swirled and is placed on a filter paper with a mar

HJ8. 2Q< HJ D;F' 3I E!I<F<@ <F"3;==P BFED "Q< "EA

through the solution.2. The stop5;"Q 3I I"EAA<@ 3DD<@3;"<=P Q<& "Q< HJ D;F' ;&&E" !<

seen. Time is recorded.+. The e6periment is repeated by using the sodium thiosuphate solution at

- 7, 0 7, 8 7 and 2 7 respectively.o o o o





Eubric Acore (f) ,ble to tabulate the data with following aspects

1( Correct titles with units

6( Complete list of temperatures

Aample answer:

Temperature ( 7)o Time (s)

-082

PAPER 3 SET

Eubric Acore1(a) ,ble to state four observations correctly

Aample answers:

=bservations at anode?lue litmus paper : turn red then bleached / decolourise

@lowing splinter : no change?lue litmus paper : no change@lowing splinter : is reindled / relighted

Eubric Acore1(b) ,ble to state the colour change in the copper )**+ chloride solution correctly

Aample answer:

The intensity of the blue solution decreases / reduced //?lue colour of solution fades gradually //

?lue solution becomes light blue

Eubric Acore1(c) ,ble to state all the variable and the action to be ta$en correctly

Aample answer:

'ame of variables #ction to be taen7oncentration of copper (BB) chloridesolution

7hange the concentration from 1. moldm to .1 mol dm5 5

@as collected at anode The change of damp blue litmus paper and glowing splinter Type of solution Fse the same copper (BB) chloride

solution

8






Eubric Acore1(d) ,ble to state the relationship between the manipulated variable and the responding

variable with direction(

Aample answer:

#he higher the concentration of ion in the solution in the electrolyte/ the higher thechance the ion discharged at anode

Eubric Acore1(e) ,ble to classify the ions correctly

2write the name or symbols of the ions(

Aample answer:7ations #nions

7opper (BB) ions, 7u$

<ydrogen ions, <$<ydro6ide ions, =<5

7hloride ions, 7l5

Eubric Acore

2$

#ble to state all the observation and inference correctly.

Aample answer:=bservation inference"hite fume is released"hite solid is formedThe mass of crucible and its contentincreases

Magnesium o6ide is formedMagnesium reacts wth o6ygen

8

Eubric Acore (b) ,ble to state all the masses accurately

Aample answer:The crucible and lid * 0.0 gThe crucible, lid and magnesium ribbon * 2.20 gThe crucible, lid and magnesium o6ide when cooled * 9.0 g

Eubric Acore

(c) )i+ The mass of Mg * 2.20 0.0* .- g)ii+ The mass of =6ygen * 9.0 2.20

* 1.8 g)iii+ The number of mole of Mg * .-/-

* .1 moleThe number of mole of = * 1.8/18

* .1 moleThe ratio of Mg : = * 1 : 1The empirical formula is Mg=





Eubric Acore (d) =(1 mole of -g reacts with =(1 mole of o8ygen&&

1 mole of -g reacts with 1 mole of o8ygen

Eubric Acore

(e) ,ble to predict and give a reason for the prediction

Aample answer:

7annot because copper is a less electropositive metal. 7opper cannot reacts witho6ygen gas to produce copper (BB) o6ide.

Eubric Acore (f) #ble to classify the o6ides into two groups, those which are basic o6ides and those

which are acidic o6ides correctly

Aample answer:

?asic o6ides #cidic o6ides• Magnesium o6ide• 7opper (BB) o6ide

• Aulphur o6ide• 7arbon dio6ide

Eubric Acore

(a)

,ble to give the statement of the problem accurately( 9esponse is in question form(

Aample answer <ow does ethanoic acid and ammonia s"4u!"# affects the coagulation of late6^

Eubric Acore(b) ,ble to state the three variables correctly

Aample answer:Manipulated : ethanoic acid and ammonia solutionEesponding : coagulate / coagulation of late6

i6ed : late6

Eubric Acore(c) ,ble to state the relationship correctly

!thanoic acid coagulates the late6 while ammonia s"4u!"# does not coagulate thelate6.

Eubric Acore(d) ,ble to state the complete list of apparatus and material as follows(

Materials: ethanoic acid .0 mol dm5 and ammonia s"4u!"#

#pparatus: ?eaer, measuring cylinder, glass rod, dropper





Eubric Acore(e) ,ble to list all the steps correctly

1. 1 cm of late6 is poured into a beaer.

. !thanoic acid is added into the beaer using a dropper.

. The mi6ture is stirred using glass rod.-. The beaer is left aside.0. The observation is recorded8. !6periment is repeated using ammonia solution to replace ethanoic

acid.

Eubric Acore(f) ,ble to tabulate the data correctly

Mi6ture =bservation3ate6 $ ethanoic acid3ate6 $ ammonia solution

2

PAPER 3 SET /

EF?EB7 A7=E!1(a)(i) ,ble to record all reading accurately with units

Aample answer :!6periment 7opper ?ronCeB 1.0 cm 1. cmBB 1.8 cm 1. cmBBB 1.0 cm 1. cm

EF?EB7 A7=E!1(a)(ii) ,ble to construct the table with correct label and unit

Aample answer :

Type of blocs ;iameter of dents (cm) #verage diameter of dents (cm)B BB BBB7opper 1.0 1.8 1.0 1.-+?ronCe 1. 1. 1. 1.1

EF?EB7 A7=E!1(b) ,ble to state the observation correctly and accurately

Aample answer :The average diameter of dents on bronCe bloc is 1.1 cm and the averagediameter of dents on copper bloc is 1.-+ cm//The siCe / diameter of dents on bronCe bloc is smaller than siCe / diameter of

dents on copper bloc//






1(c) EF?EB7 A7=E! ,ble to state the inference correctly and accurately

Aample answer :?ronCe is harder than copper //7opper is less harder than bronCe

1(d) EF?EB7 A7=E! ,ble to state operational definition correctly

Aample answer :The smaller dent produced when 1 g weight is dropped on the bloc.

1(e) EF?EB7 A7=E! ,ble to e8plain the arrangement of particles in the materials correctly

Aample answer :1. The atomic siCe of tin is bigger than copper // the atomic siCe of tin

and copper are different.. The presence of tin atoms in bronCe disrupts the orderly arrangement

of copper atoms.. Eeduces / prevent the layers of atoms from sliding over each other

easily

1 (f) EF?EB7 A7=E! ,ble to state the hypothesis correctly

Aample answer :?ronCe is harder than copper //

7opper is less harder than bronCe

1 (g) EF?EB7 A7=E! ,ble to state all three variables and all three action correctly

Aample answer :

'ame of variables #ction to be taen(i) Manipulated variable:

Type of materials //

copper and bronCe

(i) The way to manipulate variable:

Eeplace copper with bronCe

(ii) Eesponding variable:

;iameter of dent

(ii) "hat to observe in the respondingvariable:

The diameter of the dent formed oncopper bloc and bronCe bloc

(iii) 7ontrolled variable:

Mass of weight // heightof the weight // siCe of steel ball bearing

(iii)The way to maintain the controlvariable:

Fses same mass of weight // sameheight of the weight // same siCe of ball

bearing





EF?EB7 A7=E!(a) ,ble to state < correct observations(

Aample answer

Test tube =bservation

1 blue colour /solutions <igh intensity of pin colour/ solutions <igh intensity of blue colour /solutions- 3ow intensity of pin colour/ solutions0 3ow intensity of blue colour /solutions

EF?EB7 A7=E!(a) ,ble to state < correct inferences(

Aample answer

Test tube Bnference1 Bron(BB) / e$ ions formed / produced in the solutions //

Bron / e rusted/corroded/o6idised

Bron(BB) / e$ ions are not formed /produced in the solutions //Bron / e does not rust/ corrode/o6idisedMagnesium/Mg rusted/corroded /o6idised

Bron(BB) / e$ ions formed / produced in the solutions //Bron / e rusted/ corroded/ o6idised

-Bron(BB) / e$ ions are not formed /produced in the solutions //Bron / e does not rust/ corrode/o6idised //inc/n rusted/ corroded / o6idised

0 Bron(BB) / e$

ions formed / produced in the solutions //Bron / e is rusted / corroded/ o6idised

EF?EB7 A7=E!(b) ,ble to e8plain a difference in observation correctly between test tube 6 and >

Aample answer

Bron/erum/e in test tube does not rust/ corrode/ o6idised because ferum isin contact with a more electropositive metal, but iron/erum/e in test tube rusts/ corrodes/ is o6idised because ferum is in contact with a lesselectropositive metal. //Bn test tube , magnesium is more electropositive than ferum/iron and and intest tube , copper is less electropositive the ferum/iron.

EF?EB7 A7=E!(c) ,ble to state the hypothesis correctly(

Aample answer "hen a more/less electropositive metal is in contact with iron/ferum/e, the

metal inhibits/(speeds up) rusting/corrosion of iron //Bf the metal in contact with iron is higher/lower than iron/ferum/e inelectrochemical series, the rusting/corrosion of iron is slower/faster //





EF?EB7 A7=E!(d) ,ble to state all the variables in this e8periment correctly(

Aample answer (i) Manipulated variables : Type/different metal // position of metal in

electrochemical series

(ii) Eesponding variable : Eusting / corrosion // presence of blue/pin colour (iii) 7onstant variable : AiCe/mass of iron nail // type of nail // clean iron nails //temperature // medium in which the iron nail are ept

EF?EB7 A7=E!(e) ,ble to state the operational definition for the rusting of iron nail correctly(

Aample answer Eusting occurs when iron nail is in contact with copper/tin /less electropositivemetal and form blue colouration in potassium he6acyanoferrate(BBB) solution

EF?EB7 A7=E!(f) ,ble to classify all the metals correctly.

Aample answer Metals that inhibit rusting Metals that speed up rusting

Magnesium/Mginc/n

Tin/An7opper/7u

EF?EB7 A7=E!(g)(i) ,ble to state the relationship between the time ta$en and the amount of rust

formed correctly.

Aample answer The longer the time taen, the greater/bigger/larger the rust formed // Thelonger the time taen, more rust is formed // The rust formed isgreater/bigger/larger, when the time taen is longer.

EF?EB7 A7=E!(g)(ii) ,ble to predict the time ta$en for the iron nail to completely rust correctly(

#nswer 3ess than 0 days

EF?EB7 A7=E!(h)(i) ,ble to record the voltmeter readings correctly in one decimal place(

#nswer Dairs

of metalDositiveterminal

Ioltmeter reading(I)

Magnesium and iron Bron .Bron and copper 7opper .+Bron and Cinc Bron .-Bron and tin Tin .





EF?EB7 A7=E!(h)(ii) ,ble to draw a labelled diagram accurately(

Aample #nswer

EF?EB7 A7=E! (a) ,ble to -ar$e a statement of the problem accurately and must be in

question form

Aample #nswer #ble to <ow do the heat of neutralisation for reactions between acids andalalis of different strengths differ^

EF?EB7 A7=E!

(b) ,ble to state all the three variables correctly

Manipulated Iariable : different strength of acid // hydrochloric acid andethanoic acidEesponding variable : the value of heat of neutralisationi6ed variable : volume and concentration of acid // volume and

concentration of alali // polystyrene cup

EF?EB7 A7=E! (c) ,ble to state the relationship between manipulated variable and responding

variable correctly

The value of heat of neutralisation for reaction between strong acid andstrong alali is higher than of reaction between wea acid and strong alali//The value of heat of neutralisation for reaction between hydrochloric acidand sodium hydro6ide is higher than of reaction between ethanoic acid andsodium hydro6ide

EF?EB7 A7=E! (d) ,ble to state the list of substances and apparatus correctly and completely

#pparatus : Measuring cylinders, polystyrene cup with covers, thermometer Material : . mol dm sodium hydro6ide, . mol dm ethanoic acid, .

mol dm hydrochloric acid

I

Magnesium/Mg Bron/e

;ilute sulphuric

acid /< A= -

Ioltmeter





EF?EB7 A7=E! (e) ,ble to state a complete e8perimental procedure

1. Measure 0 cm of . mol dm 5 sodium hydro6ide solution, 'a=<solution using a measuring cylinder. Dour it into a polystyrene cup

with a cover.. Measure 0 cm of . mol dm 5 hydrochloric solution, <7l solutionusing another measuring cylinder. Dour it into another polystyrenecup with a cover.

. 3eave both the polystyrene cups on the table for 0 minutes. #fter 0minutes, measure and record the initial temperatures of both thesolution.

-. Dour the hydrochloric acid, <7l 4uicly and carefully into the polystyrene cup containing sodium hydro6ide solution.

0. Atir the mi6ture using the thermometer.8. Eecord the highest temperature of the reaction mi6ture.2. Eepeat steps 1 to 0 using ethanoic acid to replace the hydrochloric

acid.

EF?EB7 A7=E! (f) ,ble to tabulate the data correctly

<ydrochloric acid !thanoic acidBnitial temperature of alali, 7o

Bnitial temperature of acid, 7o

<ighest temperature of thereaction mi6ture, 7o

PAPER 3 SET

EF?EB7 A7=E!1 (a) ,ble to record all the readings accurately to two decimal points with units.

Aample answer:

#ctivity B : 8.0 cm , 8.9 cm , .0 cm

#ctivity BB : 1. cm , 0.+0 cm , +.-0 cm

EF?EB7 A7=E!1(b) ,ble to construct a table containing the following information7

1( 0eadings in the table

6( #ransfer all data from 1)a+ correctly

>( ith units

Aample answer:

Titrationnumber

Bnitial burette reading /cm

inal burette reading /cm

Iolume of acid /cm





EF?EB7 A7=E!1 .+ 1. 1.0 1.- 0.+0 1.-0 0.9 +.-0 1.00

EF?EB7 A7=E!1(c) ,ble to show all the steps to calculate the concentration of sulphuric acid correctly(

Aample answer:Atep 1: "rite the chemical e4uation:

'a=< $ < A= - Æ 'a A= $ < = -

Atep : 7alculating the number of moles of sodium hydro6ide 'umber of mol of 'a=< : .1 6 0 // .0

1Atep : 7alculating the concentration of sulphuric acid7oncentration of < A= - : ( .0 6 1 ) // .1 mol/dm

1.0 6

EF?EB7 A7=E!1(d) ,ble to state the colour change correctly

Aample answer:#ctivity B : Din change to colourless#ctivity BB : ellow change to orange

1(e) ,ble to state the correct type of acid in activity * and ** and give the correct reason(

Aample answer:Type of acid : #ctivity B use monoprotic acid and #ctivity BB use diprotic acid.Eeason : The volume of acid used in activity B is twice with the volume of acid

used in activity BB.

EF?EB7 A7=E!1(f) ,ble to state the colour change correctly

Aample answer:ellow change to orange and finally change to red

EF?EB7 A7=E!1(g) ,ble to predict the volume with the unit

Aample answer:M"%e ($# 0. cm // 0.0 0. cm

1(h) ,ble to state all the variable correctly

Manipulated Iariable : Type of acid uses // type of indicator Eesponding Ivariable : Iolume of acid to neutraliCe 0. cm of mol dm 5 sodium

hydro6ide solution // 7hange in the colour of the indicator.i6ed Iariable : 7oncentration and volume of sodium hydro6ide solution.

EF?EB7 A7=E!1(i) ,ble to state the hypothesis )relate the manipulated variable with the responding

variable+ correctly(

Aample answer:

Bf use different type of acid to neutraliCe 0. cm of 1. mol dm 5

sodium hydro6idesolution, the volume of acid use also different//;ifferent indicator used in the titration create different colour.





EF?EB7 A7=E!

EF?EB7 A7=E!1() ,ble to give the operational definition for the end2point of titration in activity *

correctly( ,ble to describe the following criteria

)i+ hat should be done

(ii) hat should be observed Aample answer:"hen hydrochloric acid is added to sodium hydro6ide solution with phenolphthalein,

pin turns to colourless.

EF?EB7 A7=E!1() ,ble to classify all the acids into strong acid and wea$ acid correctly(

Aample answer:S%"#6 $'! e$ $'!

'itric acid !thanoic acidDhosphoric acid #scorbic acid

EF?EB7 A7=E!(a) ,ble to state the inference accurately

Aample answer "hen alcohol react with carbo6ylic acid, ester is formed//!sters have sweet pleasantsmell property

EF?EB7 A7=E!(b) ,ble to construct a table correctly with the following information7

1( Columns with titles for alcohol/ carbo8ylic acid/ 3ster

6( ame of all alcohols/ carbo8ylic acid and ester

#lcohol 7arbo6ylic acid !sterMethanol !thanoic acid Methyl ethanoate!thanol Dropanoic acid !thyl propanoateDropanol Methanoic acid Dropyl methanoate

EF?EB7 A7=E!(c) ,ble to name the alcohol and carbo8ylic acid correctly(

#lcohol: Dropanol7arbo6ylic acid: ?utanoic acid

EF?EB7 A7=E!

(d)(i) ,ble to state the three variables correctly(

Aample answer Manipulated variable : <e6ane and he6eneEesponding variable : 7olour change of bromine water // colour change of

potassium manganate (IBB) solutioni6ed variable : ?romine water//acidified potassium manganate (IBB) solution





EF?EB7 A7=E!(d)(ii)

,ble to state the hypothesis accurately

Aample answer:<e6ene declourised the brown colour of bromine water, he6ane does not// <e6enedeclourised the purple colour of acidified potassium manganate(IBB)

solution, he6ane does not

EF?EB7 A7=E!(d)(iii) ,ble to predict and -ar$e e8planations accurately

#nswer 1. <e6ene. Dercentage of carbon atoms per molecule he6ene is higher than he6ane. Dercentage of carbon in he6ane * 2 6 1

+-* +0.21 %

-. Dercentage of carbon in he6ane * 2 6 1+8* +.2 %

EF?EB7 A7=E!(a) ,ble to state the problem statement accurately

Aample answer #re the effectiveness of the cleansing action of soap and detergent in hard water different^

EF?EB7 A7=E!

(b) ,ble to state the three variables accurately(

#nswer Manipulated variable: Aoap and detergentEesponding variable: !ffectiveness of cleansing action // the ability to remove

the oily stains on clothi6ed variable: cloth with oily stains, hard water

EF?EB7 A7=E!(c) #ble to state the hypothesis accurately with direction

Aample answer The cleansing action of a detergent is more effective in hard water than a soap

EF?EB7 A7=E!(d) ,ble to state the complete list of apparatus and material as follows

3ist of apparatus : beaers, , glass rod3ist of material : <ard water, soft water, soap and detergent solution, pieces of

cloths stained with oil

EF?EB7 A7=E!

(e) ,ble to state procedures correctly as follows

1. K0 5 L cm of hard water is poured into a beaer

. Aoap is added into the beaers




. # piece of cloth stained with oil is immersed in the solution-. The cloth is shaen/rubbed/stirred0. =bservation is recorded8. Eepeat steps 1 8 by using detergent .

EF?EB7 A7=E!

(f) #ble to tabulate the data correctly

Aample answer Type of cleaning agent =bservation

Aoap;etergent


answer chem p score x a plus module 2013

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