mid year paper2 f4 2010

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Jumlah

SULIT 4541/2

Nama : ……………………………………………... Kelas : …...……

SEKOLAH TUANKU ABDUL RAHMANIPOH, PERAK

PEPERIKSAAN PERTENGAHAN TAHUN TINGKATAN 42010

KIMIAKERTAS 2

Dua jam tiga puluh minit

JANGAN BUKA KERTAS SOALAN INI SEHINGGA DIBERITAHU

1. Tuliskan nama dan tingkatan pada ruang yang disediakan.

2. Calon dikehendaki membaca maklumat di halaman 2.

Kertas soalan ini mengandungi 15 halaman bercetak

Disediakan oleh: Disahkan oleh:

……………………. ………………………(EN KING ENG SENG) PN YIP YIN LENG( GURU KANAN SAINS /MATEMATIK) (KETUA PANITIA KIMIA)

[Lihat sebelah4541/2 SULIT

4541/2KimiaKertas 2Mei20102½ jam

SULIT 4541/2INFORMATION FOR CANDIDATES

1. This question paper consists of three sections: Section A, Section B and Section C.

2. Answer all questions in Section A, Section B and Section C.

3. Write your answers for Section A in the spaces provided in the question paper.

4. Write your answers for Section B and Section C on the test pad.

5. Answer questions in Section B and Section C in detail. You may use diagrams, tables, graphs and other suitable methods to explain your answer.

6. Show your working. It may help you to get marks.

7. If you wish to cancel any answer, neatly cross out the answer.

8. The diagrams in the question are not drawn to scale unless stated.

9. Marks allocated for each question or part question are shown in brackets.

10.The time suggested to answer Section A is 90 minutes, Section B is 30 minutes and Section C is 30 minutes.

11.You may use a non-programmable scientific calculator.

12.Hand in this question paper at the end of the examination.

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2

SULIT 4541/2

Section A [60 marks]

Answer all questions in this section.

The time suggested to complete Section A is 90 minutes.

1. The table below shows the melting point and boiling point of four substances.

Substances Melting point/ ºC Boiling point/ ºC

P -5 67Q -105 -38R 80 140S 801 1413

(a) What is the physical state of P and S at room temperature?

P: ....................................................................................................................

S: .................................................................................................................... [2 marks]

(b) Draw the arrangement of particles of P at room temperature.

[1 marks]

(c) Explain why substance Q has a low melting point and boiling point.

............................................................................................................................

............................................................................................................................

............................................................................................................................

............................................................................................................................ [2

marks]


3

SULIT 4541/2(d) Draw the set up of apparatus to determine the melting point of substance R.

[ 3 marks]

(e) Sketch the graph of temperature against time for substance R when it is heated from room temperature until it reaches a temperature of 100oC.

[2 marks]

Total : 10 marks

2. Diagram 2 shows the standard representation for the atoms of two elements, lithium and oxygen.

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SULIT 4541/2

(a) What is represented by the number 7 in

............................................................................................................................ [1 mark ]

(b)(i) Write the electron arrangement for an atom of:

Lithium: ..................................................................................................................

Oxygen: ................................................................................................................. [ 2 marks ]

(ii) Compare the size of the lithium atom with the oxygen atom

............................................................................................................................

............................................................................................................................ [1 mark]

(c) Complete Table 2 to show the position of oxygen in the Periodic Table.

Element Period GroupLi 2 1

O

[1 mark]

(d) Lithium reacts with oxygen to form a compound, lithium oxide.

(i) Write the formula of lithium oxide.

[1 mark]

(ii) Lithium oxide dissolves in water to produce lithium hydroxide.


5

SULIT 4541/2 Write a balance equation to represent the reaction above.

[2 marks]

(iii) Describe a chemical test to verify that lithium hydroxide solution is an alkali.

............................................................................................................................

............................................................................................................................

............................................................................................................................

............................................................................................................................[2 marks]

Total : 10 marks

3 An experiment was carried out in the school laboratory to determine the empirical formula of an oxide of copper by flowing hydrogen gas over heated copper oxide. The table below shows the results obtained.

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6

SULIT 4541/2Description Mass (g)

Combustion tube + asbestos paper 36.20

Combustion tube + asbestos paper + copper oxide 39.40

Combustion tube + asbestos paper + copper 38.76

(a) What is meant by empirical formula?

............................................................................................................................

............................................................................................................................

[1 mark]

(b) Draw a labelled diagram to show the set up of the apparatus that can be used to carry out the experiment above. You are given the following apparatus: combustion tube, delivery tubes, Bunsen burner, corks, a porcelain dish, retort stand and clamp.

[2 marks]

(c) State one precautionary step to be taken when carrying out the experiment above.

……………………………………………………………………………………............... [1 mark]

(d) Based on the results obtained,

(i) Calculate the mass of copper and oxygen that have reacted.


7

SULIT 4541/2

[1 mark]

(ii) determine the ratio of moles of copper atom to oxygen atom.[Relative atomic mass: Cu, 64; O, 16]

[1 mark]

(iii) determine the empirical formula of the copper oxide

[1 mark]

(e) Write a balanced chemical equation for the reaction between copper oxide and hydrogen.

[1 mark]

(f) Can the empirical formula of magnesium oxide be determined through the experiment above? Give one reason for your answer.

………………………………………………………………………………………………

……………………………………………………………………………………………… [2 marks]

Total: 10 marks

4.(a) The diagram below shows the results of an experiment to investigate the movement of

bromine particles in air.

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SULIT 4541/2

(i) State the name of the process involved in this experiment.

....………………………………………………………………………………...… [1 mark ]

(ii) Name the type of particle present in bromine gas, Br2

....………………………………………………………………………………...… [1 mark ]

(iii) Explain the observation in this experiment based on the kinetic theory of matter.

....………………………………………………………………………………...…

....………………………………………………………………………………...…

....………………………………………………………………………………...…

....………………………………………………………………………………...… [3 marks ]

(iv) This experiment is repeated at a higher temperature. Predict the time taken for the bromine vapour to spread throughout the space in both gas

jars.

....………………………………………………………………………………...… [1 mark ]

(b) The diagram below shows two balloons containing oxygen gas and carbon dioxide gas respectively.


9

SULIT 4541/2

Based on the given information:(i) Calculate the mass of oxygen gas in balloon A.

[Relative atomic mass: O=16 ]

....………………………………………………………………………………...… [1 mark ](ii) Calculate the volume of carbon dioxide gas in balloon B. Molar volume of gas = 24 dm3 mol-1 at room temperature and pressure]

....………………………………………………………………………………...… [1 mark ] (iii) Compare the number of gas molecules in balloon A and in balloon B.

Explain your answer.

....………………………………………………………………………………...… [2 marks]

Total: 10 marks

5. The diagram below shows part of the Periodic Table of Elements. A, B, C, D, E, F, G and H do not represent the actual symbol of the elements.

A

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SULIT 4541/2F

B D E GC H

By using the letters in the Periodic Table of Elements in the diagram above, answer the following questions.(a) Choose one element which can react with cold water.

..........................…………………………………………………………………………... [1 mark ]

(b) State whether the solution formed from the reaction in (a) is acidic or alkaline.

.…..………………………………………………………………………………... [1 mark ]

(c) Write the chemical equation for the reaction between element in (a) and water.

..………..…………………………………………………………………………. [2 marks]

(d) Which element is a transition element?

….………………………………………………………………………………….. [1 mark]

(e) Elements E and H are placed in group 17 in the periodic table. Name this group of elements. ......................................................................................................................... [1 mark]

(f) State the number of valence electrons of atom G.

………………………………………………………………………………………… [1 mark]

(g) State one of the uses of element F.

....………………………………………………………………………………...… [1 mark]

(h) The electron arrangement of M2+ ion is 2.8. In the Periodic Table of Element above, mark “M” in the box for the location of element M [1 mark]

(i) What are the particles in element E at room temperature?

…………………………………………………………………………………… [1 mark]

Total: 10 marks

6 The diagram below shows the chemical symbols which represent four elements W, X, Y and Z.


12

W 6

7

X 3

14

Y 6

40

Z 18

11

SULIT 4541/2

(a) State the number of electrons and neutrons in atom Z.

Number of electrons: ...…………….

Number of neutrons: ............……… [2

marks]

(b) (i ) Define nucleon number.

………………....………………………………………………………………...

..…………………………………………………………………………………. [1 mark]

(ii) State the nucleon number of atom Z.

........…………………………………………………………...............................[1 mark]

(c) (i) Write the electron arrangement of atom X.

…………………………………………………………………………………...[1 mark]

(ii) Draw the electron arrangement of atom X to show the position of protons, neutrons and electrons in the atom.

[2 marks]

(d) (i) Which two elements are isotopes?

…………………………………………………………………….......................[1 mark]

(ii) Explain why isotopes of an element have the same chemical properties.

…………….……………………………………..………………………………[1 mark]

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SULIT 4541/2(iii) Give one usage of the isotope mentioned in (d) (i).

…………………………………………………………………………………..[1 mark]

Total: 10 marks


13

DIAGRAM 7.2

Sodium hydroxide solution

Iron wool

Chlorine gas

SULIT 4541/2 Section B [20 marks]The time suggested to answer this section is 30 minutes.

7(a) Argon is used to fill electric bulbs because argon does not react with the white hot tungsten filament. What is the group number of argon in the Periodic Table of Elements? Explain why argon does not react with hot tungsten filament in term of electron arrangement. [4 marks]

(i) The diagram below shows the electron arrangement of atom X and atom Y from Group 1 in the Periodic Table of Elements.

X Y

(ii) Write a chemical equation for the reaction between element X and oxygen. [3 marks]

(iii)Compare the reactivity of atom X and atom Y. Explain your answer by referring to attractive forces between the nuclei and the valence electrons. [6 marks]

(iv) Lithium, 37 Li is another element in Group 1.

Predict the reactivity of lithium in its reaction with oxygen compared to element Y. [1 mark]

(c) Diagram 7.2 shows the set up of the apparatus to investigate the reaction of chlorine with iron metal.

(i) State two observations while carrying out the experiment. [2 marks]

(ii) The chemical equation for the reaction is as follow: 3Cl2 + 2Fe 2FeCl32.8 g of iron wool is completely reacted with chlorine gas. [Relative atomic mass of Cl = 35.5 and Fe = 56]Calculate the maximum mass of iron(III) chloride formed. [4 marks]

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P Q

Process I

SULIT 4541/2Section C [20 marks]The time suggested to answer this section is 30 minutes.

8A compound changed from state P to state Q under process I. The diagram below shows the arrangement of particles of the compound in state P and state Q.

Table 8.1 shows the temperature of the compound during process I.

Time (min)

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

Temperature (oC)

82 80 78 75 75 75 75 75 73 71

TABLE 8.1(a) Name process I.

Explain why the temperature remains constant from 1.5 minutes to 3.5 minutes. [2 marks]

(b) Table below shows the melting point and boiling point of a compound M.

State the physical state of compound M at 80oC and 280oC. [1

marks]

(c) Compare the particles of compound M at 80oC to those at 280oC in terms of the arrangement of particles, the movement of particles, the forces of attraction between particles and kinetic energy of particles. [4 marks]

(d) A carbon compound contains 92.3% of carbon and 7.7% of hydrogen by mass. The relative molecular mass of this compound is 78. Find the molecular formula of this compound.

[Relative atomic mass: C, 12; H, 1]

[5 marks](e) Describe how you could determine the empirical formula of magnesium oxide in the laboratory. Your description should include

procedure of experiment tabulation of result


15

Melting point (oC)

105

Boiling point (oC)

210

SULIT 4541/2

[ 8 marks]

END OF QUESTION PAPER

CHEMISTRY FORM 4MID TERM EXAM 2010

MARKING SCHEMEPAPER 2

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16

Time ( min)

Temperature / oC

SULIT 4541/2

Marking Scheme Paper 2Section A

No1

MARKING CRITERIA MARK

SUB TOTAL(a) P: liquid

Q: solid11 2

(b) 1

1

(c)The particles in Q are held together by weak attractive forces

Hence, a little amount of heat energy is required to overcome the weak forces during heating and boiling process

1

1 2

(d) Diagram

Labelled : thermometer, water and Rfunctional apparatusthe boiling tube placed inside a beaker filled with water and the substance R is below the water level in the beaker

111

3

(e)

80oC …….

Labelled both axes with units and correct shape of graphMarked 80o C as the melting point

11

2

Total 10


waterSubstance R

Thermometer

17

SULIT 4541/2

No2


SUB TOTAL(a) Nucleon number // the number of proton and neutron

J.T. (Jangan Terima)Nucleus number

1 1

(b)(i) 2.1

2.6

J. T.2:1 // 2;1 //

B. T (Boleh Terima)2,1

11 2

(ii) Lithium atom is bigger // oxygen atom is smaller 1 1

(c) Period: 2Group: 16

1 1

(d)(i)

Li2O 1 1

(ii) Li2O + H2O 2LiOHBoth the formulae of reactants and products correct Balanced equation

11

2

(iii) A red litmus paper is added to the solution in a beaker (method)The red litmus paper changes to blue colour(observation )

J. T.The solution is tested with a red litmus paper

1

12

Total

10

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18

Dry hydrogen gas

Oxide of copper

Heat

SULIT 4541/2

No3


SUB TOTAL(a) A chemical formula that gives the simplest whole number ratio of

atoms of each element in the compound.1 1

(b)Burning of excess hydrogen

- functional - label( oxide of copper, dry hydrogen gas and heat)

11

2

(c) Pass the dry hydrogen gas through the combustion tube for a few minutes before the oxide of copper is heated //

The flow of hydrogen gas must be continuous.//

The flow of hydrogen gas is continued throughout the cooling of the product

Any one answer correct

11

(d)(i)

mass of copper : 38.76 – 36.20 = 2.56gmass of oxygen : 39.40 – 38.76 = 0.64g

Both the mass are correct to get 1 mark

1 1

(ii) Cu : O2.56/64 : 0.64/16 0.04 : 0.04 1 : 1

1 1

(iii) CuO 1 1(e) CuO + H2 Cu + H2O 1 1

(f) No.

Magnesium is more reactive than hydrogen.// Magnesium is above hydrogen in the Reactivity Series.

1

1

2

Total

10


19

SULIT 4541/2

No4


SUB TOTAL(a)(i)

Diffusion 1 1

(ii) Molecules 1 1

(iii) The air and bromine molecules/particles moves randomly in all directions

The bromine molecules / particles move from region of higher concentration to region of lower concentration

Finally, the bromine molecules / particles occupied the empty spaces between the air particles and the 2 gas jars are filled with bromine.

1

1

13

(iv) Less than 10 minutes// any reasonable answer below 10 minutes

1 1

(b)(i)

Mass of oxygen gas = 32 g mol -1 x 0.5 mol = 16g 1 1

(ii) Volume of carbon dioxide gas= 0.5 mol x 24 dm3 mol -1

= 12 dm31 1

(iii) Same number of moleculesBecause the number of moles of carbon dioxide and oxygen are the same

1

12

Total

10

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20

SULIT 4541/2

No5


SUB TOTAL(a) B // Na // sodium 1 1(b) alkaline 1 1

(c) 2B + 2H2O 2BOH + H2

Or

2Na + 2H2O 2NaOH + H2

Formulae of reactants and products are correctBalanced equation

11

2

(d) C // Iron // Fe 1 1(e) Halogens 1 1(f) 8// eight 1 1

(g) Used in advertising light // neon light 1 1(h) Mark correctly in the table 1 1(i) molecules

Total

10

No6


SUB TOTAL(a) Electrons : 18

Neutrons : 2211

2

(b)(i)

The total number of neutrons and protons in an atom 1 1

(II) 40 1 1

(c)(i)

2.1 1 1

(ii) Correct diagram showing the nucleus and 2 shellsLabelled electron, protons and neutrons

11

2

(d)(i)

W and Y 1 1

(ii) Because they have similar electron arrangement// because the number of electrons are the same

1 1

(iii) To determine the age of fossils or artifacts or any correct answers

1 1

Total

10


21

SULIT 4541/2

No MARKING CRITERIA MARK

SUB TOTAL7

(a) Group 18 / 18 Argon atom has attained octet electron arrangement/

Argon atom has 8 valence electrons/Argon atom’s outermost shell is completely filled with electrons.

This electron arrangement is stable //Argon is inert / unreactive.

Argon atom does not need to gain, lose or share electrons with other elements.

11

1

1 4

(b)(i)

Correct symbol/formula of the reactants. Correct symbol/formula of the product. Balance equation

Answer:4X + O2 2X2O

111 3

(ii) Atom Y is more reactive than atom X.

The atomic size Y / the size of atom Y is greater than atom X.//The valence electron of atom Y is further away from the nucleus compare to atom X.

The attraction forces between nucleus and valence electron of atom Y is weaker than atom X.//It is easier for atom Y to donate / release / lose the valence electron compare to atom X.

Or

Atom Y is more reactive. The valence electron of atom Y is further away from the

nucleus//Atom Y has bigger atomic size.

The attraction forces between nucleus and valence electron of atom Y is weak.

Atom X is less reactive. The valence electron of atom X is closer to the nucleus

//Atom XY has smaller atomic size. The attraction forces between nucleus and valence electron

of atom X is strong.

1+1

1+1

1+1

11

1

11

1

6

(iii) The reaction of lithium with oxygen is less reactive.

1 1

(c)(i)

The iron wool burns vigorously with a bright flame. A brown solid is formed.

11 2

(ii)

Number of moles of iron =

2. 856

= 0.05

2 moles of Fe produce 2 moles of FeCl3

1

4541/2 SULIT

22

SULIT 4541/20.05 mole of Fe produce 0.05 mole of FeCl3

0.05 mole of FeCl3 = 0.05 (56+3(35.5)) g = 0.05 162.5 = 8.125 g

1

1

1 4

20

No MARKING CRITERIA MARK

SUB TOTAL8(a) Freezing

The energy released during freezing is equal to the heat energy lost to the surrounding.

1

1 2

(b) At 80oC : Solid At 280oC : Gas

Both must be correct to get 1 mark

11

(c)Temperature 80oC (Solid) 280oC (Gas)

Arrangement of particles

Particles are orderly and closely packed together.

Particles are far apart.

Movement of particles

Vibrating and rotating about in their fixed positions.

Particles move randomly and rapidly in all directions.

The forces of attraction

Strong Weak

Kinetic energy Low High

Note: 1 mark for each correct comparison.

1

1

1

1

4

(d) C H

% 92.3 7.7Consider 100 of compound,

Mass (g) 92.3 7.7


23

SULIT 4541/2Mol atom 92.3/12 7.7/1 = 7.69 7.7

Simplest Ratio 1 : 1

Empirical formula : CH

Let the molecular formula be (CH)n

Hence, ( 12 + 1) n = 78 n= 6

Hence the molecular formula is C6H6

1

1

1

1

1

5

(e)Procedure:

1. A crucible is weighed together with its lid, and the mass is recorded.

2. A 20 cm magnesium ribbon is cleaned with sandpaper and is rolled into a coil and placed in the crucible.

3. The crucible and its content are weighed again, and the mass is recorded.

4. The crucible and its content are heated strongly without the lid. When the magnesium starts to burn, the crucible is covered with its lid.

5. The crucible lid is raised at intervals to allow oxygen gas to enter and reacts with magnesium coil

6. When the burning stops, the crucible is cooled and weighed again together with its content.

7. The process of heating, cooling and weighing are repeated until a fixed mass is obtained. The fixed mass is recorded

Mass of crucible + lid (g)Mass of crucible + lid + magnesium (g)Mass of crucible + lid + magnesium oxide (g)

1

1

1

1

1

1

1

1

8

Total 20

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24

mid year paper2 f4 2010

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