1

A

11

D

21

A

31

D

2

C

12

D

22

C

32

C

3

B

13

C

23

D

33

D

4

A

14

D

24

B

34

C

5

A

15

D

25

B

35

B

6

C

16

B

26

B

36

C

7

B

17

B

27

B

37

C

8

D

18

D

28

A

38

C

9

D

19

A

29

B

39

B

10

D

20

D

30

A

40

D

A1

(a)

nickel

[1]

(b)

aluminum / sodium

[1]

(c)

phosphorus / nitrogen

[1]

(d)

phosphorus / nitrogen

[1]

(e)

nickel/ iron

[1]

A2

(a)

C

[1]

(b)

C

[1]

(c)

D and E

[1]

(d)

[2]

A3

(a)

(i)

Each member differ from the next member by a -CH₂ group

OR

Members undergoes similar chemical reactions but with different reactivity rate

[1]

(ii)

C_nH_2n

[1]

(b)

(i)

2C₃H₆ + 9O₂ ® 6CO₂ + 6H₂O

[1]

(ii)

substitution

[1]

(c)

Name : propene

H H H

ç ç ç

H – C – C = C – H

ç

H

[1]

[1]

A4

(a)

CaCO₃ ® CaO + CO₂

[1]

(b)

(i)

CaO + H₂O ® Ca(OH)₂

[1]

(ii)

calcium carbonate

[1]

(c)

to lime the soil

[1]

(d)

no of moles of Ca₃SiO₅

= __Mass__

Mr

= ______912_________

3(40) + 28 + 5(16)

= __912_

228

= 4

no of moles of Ca(OH)₂ = 4 x 3

2

= 6

Mass of Ca(OH)₂

= no of moles x Mr

= 6 x [ 40 + 2(16 + 1)]

= 6 x 74

= 444 g

[1]

[1]

[1]

A5

(a)

SiC

[1]

(b)

In graphite, each carbon atom has one outermost shell electron which is not used to form covalent bonds. These electrons can move along the layers to act as charge carriers. Hence graphite can conduct electricity.

In silicon carbide, all the outer shell electrons are used for bonding. There are no free electrons that can act as charge carriers.

[1]

[1]

(c)

(i)

Silicon carbide has a macromolecular structure. The silicon and carbon atoms are strongly bonded together in a network of covalent bonds. A large amount of energy is required to overcome the bonds hence silicon carbide has a high melting points

[1]

(ii)

Diamond consists of the same type of atoms whereas silicon carbide consist two different types of atoms. Thus the covalent bonds between the carbon atoms are stronger than those between carbon and silicon atoms.

[1]

(d)

4.40 g

Both structure contains only carbon atoms , therefore 1.20 g of graphite and diamond have same no of moles of carbon and hence produce same mass of CO₂

[1]

A6

(a)

‘fizzing’ would be observed

lithium moves around on the surface of the water

[1]

[1]

(b)

2Li + 2H₂O ® 2LiOH + H₂

[1]

(c)

Lithium atom loses electron to form a lithium ion hence oxidation had take place.

[1]

(d)

An extremely explosive reaction take place.

The rubidium will melts and catches fire.

[1]

[1]

A7

(a)

(i)

When there is an increased in the percentage of carbon dioxide in graph 2, there is corresponding increase in the average temperature of the earth’s surface in graph 1.

[1]

(ii)

There is a decrease in crops yields world wide as areas that are currently covered by vegetation may become deserts.

Melting of large quantities of ice in the north and south Pole will cause the level of sea water to rise and flood low-lying countries

[1]

[1]

(b)

[2]

(c)

(i)

methane

[1]

(ii)

bacteria decay of vegetation

[1]

(iii)

In the presence of sunlight, chlorofluorocarbons decomposed to form chlorine atoms which react with the ozone molecules in the ozone layer to form chlorine oxide and oxygen, thus destroying the ozone layer. The ultra-violet light can reach the earth through holes in the ozone layer.

[1]

[1]

B8

(a)

from fertilisers

[1]

(b)

Excess phosphates promotes excessive growth of algae. When the algae die and decomposed by bacteria, the bacteria use up the available oxygen. The decreased in oxygen supply causes the deaths of fishes and aquatic organisms.

[1]

[1]

[1]

(c)

(i)

Add aqueous sodium hydroxide and aluminium foil to a portion of nitrate ions. Warm the mixture. A colourless and pungent gas evolved and turned moist red litmus blue. This shows the presence of nitrate ions.

[1]

[1]

(ii)

river water also contains minerals and phosphates ions which may also react with the aqueous sodium hydroxide

[1]

(d)

no of moles of I₂

= __0.508___

2(127)

= __0.508__

254

= 0.002

no of moles of O₂ = 0.002 ¸ 2

= 0.001

conc of oxygen

= 0.001 ¸ 2000 x 1000

= 5 x 10^–4 mol/dm³

[1]

[1]

[1]

B9

(a)

H⁺ (aq) + OH^- (aq) → H₂O (l)

[1]

(b)

The reagents used are potassium hydroxide and hydrochloric acid.

KOH + HCl → KCl + H₂O

Pipette 20.0 cm³ of potassium hydroxide into a conical flask and add a few drops of a suitable indicator.

Titrate it against hydrochloric acid until the end-point is reached that is the indicator changes colour. Note the volume of hydrochloric acid added, V₁ cm³.

Repeat the procedure by titrating 20.0 cm³ of potassium hydroxide with V₁ cm³ of acid but without the addition of indicator.

Pour the mixture into evaporating dish. Heat the mixture to evaporate most of the water.

Allow the hot solution to cool for crystals to form.

Filter and obtain the crystals.

Dry the crystals between pieces of filter paper

[1]

[1]

[1]

[1]

B9

(c)

No of moles of K₂CO₃

= _____3.45________

2(39) + 12 + 3(16)

= 0.025

No of moles of K₂SO₄ = 0.025

Mass of K₂SO₄

= 0.025 x [ 2(39) +32+ 4(16)]

= 0.025 x 174

= 4.35 g

[1]

[1]

[1]

(d)

[1]

[1]

B10

(a)

Brass is a mixture of metals but zinc and copper are pure metals

[1]

(b)

(i)

green

[1]

(ii)

Zn(NO₃)₂ + 2NaOH → Zn(OH)₂ + 2NaNO₃

A white precipitate of zinc hydroxide is formed. The white precipitate is soluble in excess aqueous sodium hydroxide to give a colourless solution.

Cu(NO₃)₂ + 2NaOH → Cu(OH)₂ + 2NaNO₃

A light blue precipitate of copper (II) hydroxide is formed. The blue precipitate is insoluble in excess aqueous sodium hydroxide.

[1]

[2]

[1]

[1]

(c)

(i)

B is zinc chloride

C is copper

[1]

[1]

(ii)

Zn(s) + 2H⁺ → Zn²⁺(aq) + H₂(g)

[1]

B11

(a)

ester linkage

[1]

(b)

(i)

Amino acids

[1]

(ii)

Nylon contains the same linkage as proteins so it also may be hydrolysed into its monomers by concentrated hydrochloric acid

[1]

(c)

(i)

H Cl H Cl H Cl

ç ç ç ç ç ç

– C – C – C – C – C – C –

ç ç ç ç ç ç

H H H H H H

[1]

(ii)

The intermolecular forces of attraction between the poly(chloroethene) are weak hence only a small amount of energy is required to overcome the bonds hence give rise to its low melting point.

[1]

(iii)

The reddish brown aqueous bromine will turn colourless quickly in the presence of chloroethene.

The type of reaction is addition reaction.

Poly(chloroethene) does not consists of carbon-carbon double bonds hence it will not react with bromine.

[1]

[1]

[1]

(d)

Poly(ethene) is non-biodegradable hence it cannot be decomposed by bacteria. Thus, it will cause long term litter problem.

[2]