Classified Chemistry IGCSE Paper_3_Topic 1

1 - States Of Matters Mostafa Barakat (0100 165 44 62)

1

Topic 1

States of matters

Kinetic theory of particles

Diffusion

Classified Chemistry IGCSE Paper_3_Topic 1

1 - States Of Matters Mostafa Barakat (0100 165 44 62)

2

1) June 2002 Q (5_a, b)

5 (a) The Kinetic Theory explains the properties of solids, liquids and gases in terms of the movement of particles.

Liquids and gases both take up the shape of the container but a gas always fills the container. Explain this, using the ideas of the Kinetic Theory.

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(b) The following apparatus can be used to measure the rate of diffusion of a

gas.

(i) What measurements would need to be taken to calculate the rate of diffusion of a gas?

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(ii) Which gas, carbon dioxide or sulphur dioxide, would diffuse faster? Explain your choice.

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Classified Chemistry IGCSE Paper_3_Topic 1

1 - States Of Matters Mostafa Barakat (0100 165 44 62)

3

2) June 2003 Q (4_b)

(b) When nitrogen dioxide is cooled, it forms a yellow liquid and then pale yellow crystals.

These crystals are heated and the temperature is measured every minute. The following graph can be drawn.

(i) Describe the arrangement and movement of the molecules in the region A–B.

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(ii) Name the change that occurs in the region B–C

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3) Nov 2005 Q (2_a)

2) Ethanoic acid is a colourless liquid at room temperature. It has the typical acid properties and forms compounds called ethanoates.

Classified Chemistry IGCSE Paper_3_Topic 1

1 - States Of Matters Mostafa Barakat (0100 165 44 62)

4

a) A pure sample of ethanoic acid is slowly heated from 0 oC to 150 oC and its temperature is measured every minute. The results are represented on the graph below.

(i) Name the change that occurs in the region D to E.

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(ii) What would be the difference in the region B to C if an impure sample had been used?

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(iii) Sketch on the graph how the line would continue if the acid was heated to a higher temperature.

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(iv) Complete the following table that compares the separation and movement of the molecules in regions C to D with those in E to F.

C to D E to F

Separation (distance between particles)

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Movement of particles Random and slow ……………………. ……………………..

Can particles move apart to fill any volume?

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4) June 2010 Q (2_i)

2) Ozone is a form of oxygen. Ozone is present in the upper atmosphere and it prevents dangerous solar radiation from reaching the Earth’s surface. Some of the chemicals that diffuse into the upper atmosphere decompose ozone. Chemicals that have this effect are methane (CH4), chloromethane (CH3Cl) and an oxide of nitrogen (NO2).

(i) Which of these three chemicals diffuses the most slowly? Give a reason for your choice.

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Classified Chemistry IGCSE Paper_3_Topic 1

1 - States Of Matters Mostafa Barakat (0100 165 44 62)

5

5) Nov 2010 [33] Q (6_a, ii, b)

6 The Kinetic Theory explains the properties of matter in terms of the arrangement and movement of particles.

(a) Nitrogen is a gas at room temperature. Nitrogen molecules, N2, which are spread far apart move in a random manner at high speed.

(ii) How does the movement and arrangement of the molecules in a crystal of nitrogen differ from those in gaseous nitrogen?

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(b) Use the ideas of the Kinetic Theory to explain the following.

(i) A sealed container contains nitrogen gas. The pressure of a gas is due to the mo lecu les o f t he gas h i t t ing the wa l l s o f t he con ta ine r . Explain why the pressure inside the container increases when the temperature is increased.

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(ii) The following apparatus can be used to measure the rate of diffusion of a gas.

The following results were obtained

Explain why nitrogen diffuses faster than chlorine.

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Explain why the nitrogen diffuses faster at the higher temperature.

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Classified Chemistry IGCSE Paper_3_Topic 1

1 - States Of Matters Mostafa Barakat (0100 165 44 62)

6

6) June 2012 [31] Q (1_a)

1) The diagram below shows part of the Water Cycle.

(a) (i) State the name of each of the following changes of state.

2 ( ) 2 ( )l gH O H O

name ..................................................................................................................

2 ( ) 2 ( )g lH O H O

name ..................................................................................................................

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(ii) Which one of the above changes of state is exothermic? Explain your choice.

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7) June 2012 [32] Q (1_c)

(c) When liquid nitrogen boils the following change occurs.

N2(l) N2(g)

The boiling point of nitrogen is very low even though the bond between the atoms in a nitrogen molecule is very strong. Suggest an explanation.

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Classified Chemistry IGCSE Paper_3_Topic 1

1 - States Of Matters Mostafa Barakat (0100 165 44 62)

7

8) Nov 2012 [32] Q (2)

2 The diagram shows a heating curve for a sample of compound X.

(a) Is X a solid, a liquid or a gas at room temperature, 20 °C?

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(b) Write an equation for the equilibrium which exists in region BC.

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(c) Name the change of state which occurs in region DE.

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(d) Explain how the curve shows that a pure sample of compound X was used.

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9) Nov 2012 [33] Q (3)

3 (a) A small amount of liquid bromine is added to a container which is then sealed.

2(l) 2(g)Br Br

Use the ideas of the Kinetic Theory to explain why, after about an hour, the bromine molecules have spread uniformly to occupy the whole container.

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Classified Chemistry IGCSE Paper_3_Topic 1

1 - States Of Matters Mostafa Barakat (0100 165 44 62)

8

(b) The diagrams below show simple experiments on the speed of diffusion of gases.

Complete the following explanations. Diagram 1 has been done for you.

Diagram 1

There is air inside and outside the porous pot so the rate of diffusion of air into the pot is the same as the rate of diffusion of air out of the pot. The pressure inside and outside the pot is the same so the coloured liquid is at the same level on each side of the tube.

Diagram 2

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Classified Chemistry IGCSE Paper_3_Topic 1

1 - States Of Matters Mostafa Barakat (0100 165 44 62)

9

Diagram 3

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