skema pppa kimia k2 spm 2011 selangor kertas 2

7/28/2019 Skema Pppa Kimia k2 Spm 2011 Selangor Kertas 2

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SULIT 4541/2

4541/2 2011 Hak Cipta Jabatan Pelajaran Negeri Selangor SULIT

1

PERATURAN PEMARKAHANPROGRAM PENINGKATAN PRESTASI AKADEMIK

PEPERIKSAAN PERCUBAAN

SPM 2011

KIMIA KERTAS 2SECTION A

Question Description Marks

1 (a) (i) [Able to state the meaning of nucleon number]

Nucleon number is the sum of the number of protons and neutrons in thenucleus of an atom

1

(ii) [Able to state the number of neutron]

61

(iii) [Able to write correct symbol]

1

.....3

(b) (i) [Able to write electron arrangement]

2.61

(ii) [Able to write number of valence electron]

61

.....2

(c) [Able to state pair of isotopes and explain]

Q and R

Have the same proton number but different nucleon number / Have thesame number of protons but different number of neutrons

1

1.2

(d) (i) [Able to calculate relative molecular mass]

12 x 6 + 12 + (6 x 16) = 1801

(ii) [Able to write empirical formula]

QP2S 1.......2

9

Q12

6


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2


2 (a) [Able to state a halogen]

S 1......1

(b) (i) [Able to state a chemically unreactive element]P 1

(ii) [Able to give a reason]

Atom P has 8 electrons in the outermost shell//attained the octet stable

electron arrangement// maximum number of electrons in the outer shell1

......2

(c) (i) [Able to write electron arrangement]

2,8,3 // 2.8.3 1

(ii) [Able to write correct formula]

R3+ / Al3+

1 ......2

(d) (i) [Able to state type of compound]

Ionic 1

(ii) [Able to draw electron arrangement with correct no of shell and electrons]

[Able to draw electron arrangement with correct charge and label of the

ions]

1

1

......3

(e) [Able to state one special characteristic]

Exists as a coloured compounds/ ions// has several oxidation numbers//can form complex ions // can act as catalyst

1

1

9

Q

X

X

XX

XX

XX

XX

+

S

X

X

XX

XX

XX

XX

_X X

XX

XX

XX


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3


3 (a) (i) [Able to define acid]

Chemical/substance that ionises in water to produce hydrogen ion/ H + ion 1

(ii) [Able to identify X acid]

Ethanoic acid/propanoic acid/any carboxylic acid 1

(iii) [Able to explain ]

1.Nitric acid ionises completely in water to produce a higher concentration

of H + ion//Ethanoic acid ionises partially in water to produce a lowerconcentration of H + ion

2. the higher the concentration of H+ ,the lower the pH value

1

1

(iv) [Able to state one observation]

Effervescence / gas bubbles formed /calcium carbonate dissolves

1

......5

(b) (i) [Able to name saltY]

Copper(II) sulphate1

(ii) [Able to suggest solution Z]

Sodium/potassium/ammonium carbonate/carbonic acid

a: in the form of formula

1

(iii) [Able to write correct and balance ionic equation]

Cu2+

+ CO32-

CuCO3

1

(iv) [Able to show calculation correctly]

Number of mole of H2SO4 = 50 x 0.2 // 0.01 mol

1000

Based on chemical equation;

1 mol H2SO4 : 1mole CuSO4 /salt Y0.01ol H2SO4 : 0.01 mol CuSO4 /salt Y

Mass salt Y / CuSO4 = 0.01 x 160 // 1.6 g

1

1 5

10


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4


4 (a) (i) [Able to draw a labelled functional apparatus set-up and the collection of

hydrogen gas ]Functional diagramLabel 1

1

(ii) [Able to write the balanced chemical equation]

Mg + 2HCl MgCl2 + H21

(iii) [Able to calculate correctly]

Number of moles of HCl = 0.1 X 50 = 0.005 mol1000

2 mol of HCl produce 1 mol of H2

0.005 mol of HCl produce 0.0025 mol of H2

Maximum volume of H2 = 0.0025 x 24 = 0.06 dm3 // 60 cm3

1

1

........5

(b) (i)

(ii)

[Able to calculate ]Experiment I = 30 // 0.1 cm

3s

-1

300

Experiment II = 45 // 0.15 cm3 s-1

300

1

1

(c) [Able to explain using the collision theory correctly]

The rate of reaction in experiment II is higher than that of experiment I. Copper(II) sulphate solution lowers the activation energy of the reaction

in experiment II. The frequency ofeffective collisions between hydrogen ions and zinc

atoms increases in experiment II.

1

1

1

........5

Total 10

hydrochloric acid

Calcium carbonate powder

Water


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5


5 (a) [Able to define heat of precipitation]

Heat energy released when 1 mol of lead(II) sulphate precipitate is formedfrom 1 mol of Pb2+ ion/lead(II) ion and 1 mol of SO4

2- ion/sulphate ion1

........1

(b) [Able to state one observation correctly]

White precipitate is formed /polystyrene cup becomes warm/thermometerreading increases

1

........1

(c) [Able to give function of polystyrene cup]

Good heat insulator/ can reduce (minimize) heat loss to the sorrounding

r : prevent

1

........1

(d) (i) [Able to calculate heat released in experiment]

Mole of Pb2+/SO42- = 50 x 2.0 // 0.1 mol1000

1 mol Pb2+

releases 50400 J

0.1mol Pb2+ releases 5040 J// 0.1 X 50400//5040 J//5.04 kJ

1

1

(ii) [Able to calculate temperature changed]

5040 = 100 x 4.2 x

=12o C

1

1........4

(e) [Able to draw energy level diagram]

1. Label the energy axis & correct energy level of the reactants and product2. Correct chemical equation// ionic equation 1

1 .......2

(f) [Able to give reason correctly]

The heat of precipitation of lead(II) sulphate only involves Pb2+ ion and

SO42- ions.

1

1

Pb +SO4-

PbSO4

Energy

H = -50.4kJ/mol -1


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6

(g) [Able to state one precaution]

Stir the solution mixture continuously

//immediately and carefully pour lead (II) nitrate/potassium sulphatesolution into the polystyrene cup

//Record the highest temperature of the mixture

1

..1

11


6 (a) (i) [Able to name the oxidising agent]

Copper(II) sulphate // copper(II) ion 1

(ii) [Able to suggest replacement for zinc]

Magnesium / Mg 1

(iii) [Able to explain observation]

Copper(II) ions / Cu2+ are reduced to form Cu atom // Concentration of

copper(II) ion/Cu2+ decreases

1 ......3

(b) (i) [Able to state change in oxidation number]

0 to -1 1

(ii) [Able to write balanced ionic equation]

Br2 + 2I- I2 + 2Br

1

1

(iii) [Able to predict observation]

No change is observed1

......4

( c) (i) [Able to state function of sulphuric acid]

To allow ions to pass through it. 1

(ii) [Able to calculate oxidation number]

x + 4(-2) = -1x = +7

11

(iii) [Able to state the oxidising agent]

Acidified potassium dichromate(VI) solution // Bromine water // Chlorine

water // Any suitable oxidising agent1

.......4

11


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7

SECTION B


7 (a) [Able to write formula all ions]

Cu2+ , H+, SO42-, OH- 1

.....1

(b) (i) [Able to give factor concern]

Type of electrode 1

.....1

(ii) [Able to explain observation and write half equation]

At anode

Copper atom releases electrons/ is oxidised

Observation : anode becomes thinner

Cu Cu2+ + 2e

Product is copper (II) ion

At cathode

Copper (II) ion receives electron // copper (II) ion is discharged/ is reduced

Observation : cathode becomes thicker / brown solid is deposited

Cu2+

+ 2e Cu

Product is copper metal / atoms

1

1

1

1

1

1

1

1.....8

(c) [Able to explain electroplating process]

The iron ring is connected to the negative terminal / cathode of a cell

A silver plate is connected to the positive terminal/ anode of the same cell

The iron ring and silver plate is immersed in a silver nitrate solution in abeaker

Leave the apparatus set up for 30 minutes

1

1

1

1.....4

(d) (i) [Able to state cell terminals]

Negative terminal is zinc electrode / plate

Positive terminal is copper electrode / plate

1


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8

(ii) [Able to state and explain observation]

The blue colour is decolourised / turns pale blue

Copper(II) ion receives electrons to form copper atom

the concentration of Cu2+

ion decreases

1

1

1 .......4

(e) [Able to explain voltmeter reading]

Voltmeter reading is bigger / increases

Because the distance between zinc and silver is greater than between zincand copper in the Electrochemical Series / Silver is below copper in theElectrochemicalSeries / Silver is less electropositive than copper

1

1

.....2

20


8 (a) (i) [Able to name atom X]

Zinc 1

(ii) [Able to compare cooper from brass]

-Brass is harder than copper.

-Atoms in pure copper are of the same size, while atoms in brass are of

different sizes.

-The atoms in pure copper are arranged in orderly arrangement, while inbrass there is no orderly arrangement of atoms / arrangement of atoms isdisrupted

-In pure copper the atoms can easily slide over each other, while in brassthe atoms are prevented from sliding over each other

1

1

1

1

.....5

(b) (i) [Able to name and draw the structural formula]

Polypropene

1

1

C C

H

H H

CH3 n


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9

(ii) [Able to state properties of Y make it usefull explain the enviromentaleffect]

Polymer Y is very stable/ does not corrode.

It is non- biodegradable

Burning of polymer produces acidic/toxic gas//cause acid rain// clogdrain /flash flood.

1

1

1

.......5

(c) (i) [Able to state hydrophilic part of soap anion]

Y 1

(ii) [Able to name alkali in preparing soap]

Sodium hydroxide 1

(iii) [Able to explain soap effectiveness in hard water]

Hard water contains calcium and magnesium ions.

These ions react with the soap anions to form scum/ a precipitate.A more effective cleaning agent would be detergent.

1

11

........5

(d) (i) [Able to state type of medicine and function]

Type of medicine: Antibiotics

Its function is to kill or slow down the growth of bacteria

1

1

(ii) [Able to state and explain correct usage of medicine]

The full course of antibiotics must be finished.

This is to ensure that all the bacteria are killed.

Otherwise the remaining bacteria may become more resistant to theantibiotic.

1

1

1

.......5

20


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10

SECTION C


9

(a) (i)

[Able to define hydrocarbon]

Hydrocarbon is a compound that contains carbon and hydrogen only. 1

(ii) [Able to describe correctly]

Bubble R and Q into two different test tubes containing bromine water/acidified potassium manganate(VII) solution.

R: brown/ purple solution turns colourless

Q: No change

1+1

1

1

1 ...5

(b) (i) [Able to write chemical equation]

C3H7OH + 9/2O2 3CO2 + 4H2O 1

(ii) [Able to calculate correctly]

No. of moles of C3H7OH = 10/60 = 1/6

1 mole C3H7OH produces 3 mol CO2

1/6 mol C3H7OH -------------- 3 x 1/6 = 0.5 mol CO2

Volume of CO2 = 0.5 x 24 dm3

= 12 dm3// 12000 cm

3

1

1

1

4


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11

(c) (i) [able todraw and label the set up of the apparatus correctly]Functional diagramLabel

1. Soak glass wool with alcohol P and insert in a combustion tube.

2. Heat porcelain chips strongly. (Heat glass wool to vapourise alcohol P)

3. Collect gas R in a test tube using downward displacement of water.

1

1

11

1

1

1

..7

(d) [Able to name, write equation and state property]

Propyl ethanoate

CH3COOH + C3H7OH CH3COOC3H7 + H2OSweet, fruity smell// insoluble in water

1

1+1

1 .4

20

Glass wool

dipped inalcohol P

Porcelain

chips

Gas R


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12


10 (a) (i) [Able to draw the graph correctly]

Both axes are labelled and with unit

All points are transferred correctly

Shape of the graph is correct

(Refer page 14)

1

1

1

(ii) [Able to do the following]

- show the minimum volume of sodium chloride solution 1.0 mol dm-3

on the graph drawn in (a)

- state the minimum volume of sodium chloride solution

1.0 mol dm-3 is 5.0 cm3

(Refer page 14)

1

1

(iii) [Able to calculate correctly]The number of moles of silver ion = 5.0 x 1.0 // 0.005 mol

1000

The number of moles of chloride ion = 5.0 x 1.0 // 0.005 mol1000

0.005 mol of Ag+

react completely with 0.005 mol Cl-

1 mol of Ag+ will react completely with 1 mol of Cl -

1

1

1

(iv) [Able to write an ionic equation correctly]Formula of reactants correct

Formula of product correct

Ag+

+ Cl-

AgCl

1

.

.....1

(b) (i) [Able to describe the preparation of magnesium sulphate solution.]

1. Add (20-50) cm3 [0.1-2.0] mol dm-3 aqueous magnesium nitrateto (20-50) cm

3[0.1-2.0] mol dm

-3aqueous sodium carbonate

solution.

2. Stir the mixture and then filter3. Wash the residue//magnesium carbonate with distilled water4.

Add the residue to sulphuric acid until excess

5. The mixture is then filter to remove access residue//magnesiumcarbonate

6. The filtrate is magnesium sulphate salt solution

1

1

1

11

1


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13

(ii) [Able to state the confirmatory test correctly]

1. Pour the filtrate into 2 test tube.2. Add sodium hydroxide solution drop by drop until excess

into one of the test tube.

3. White precipitate insoluble in excess sodium hydroxide isformed shows the present of magnesium ion.

4. Add nitric acid followed by barium nitrate solution into anothertest tube .

5. White precipitate is formed shows the present of sulphate ion.

1

1

1

1

1 Max 11

Total 20


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14

1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

X XXX

X

X

X

X

Volume of 1 .0 mol dm-

sodium chloride solution (cm ) //Isi padularutan

natrium

Height of the precipitate (cm)

Tinggi mendakan (cm)

Question 10 (a) (i)

5.0 cm of 1 .0 mol dm

-

sodium chloride solution

skema pppa kimia k2 spm 2011 selangor kertas 2

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