AQA GCSE PHYSICS · PAPER 1 · FOUNDATION & HIGHER
Exam Practice: Changes of state
Changes of state · Particle model of matter · Lesson 2 of 6 · 13 marks · 14 minutes
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Instructions
• Answer all the questions.
• Write your answers in the spaces provided.
• The marks for each question are shown in brackets - use this as a guide to how much to write.
• The answers are on separate pages at the back. Attempt every question before you look at them.
• Answer all questions. Use the mark allocation as a guide to how much to write.
Question 1 COMPLETE (3 marks)
Name the change of state when (a) a solid changes to a liquid (b) a gas changes to a liquid (c) a solid changes to a gas without becoming a liquid.
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(Total for Question 1 = 3 marks)
Question 2 EXPLAIN (2 marks)
A 200 g ice cube melts. State the mass of the water and explain your answer.
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(Total for Question 2 = 2 marks)
Question 3 EXPLAIN (2 marks)
Explain the difference between a physical change and a chemical change.
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(Total for Question 3 = 2 marks)
Question 4 DESCRIBE (3 marks)
Describe what happens to the arrangement and movement of the particles when a solid melts.
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(Total for Question 4 = 3 marks)
Question 5 EXPLAIN (3 marks)
A student heats water until it boils. The water changes to steam. Explain, in terms of particles, why the steam takes up much more space than the water.
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(Total for Question 5 = 3 marks)
TOTAL FOR PAPER = 13 MARKS
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Answers and mark scheme
Check your answer only once you have written one.
Question 1 (3 marks)
(a) melting (b) condensing (c) sublimation
• Melting 1 mark
• Condensing 1 mark
• Sublimation 1 mark
Question 2 (2 marks)
200 g. Mass is conserved because the particles are the same; only their arrangement has changed.
• 200 g 1 mark
• Mass conserved or the same number of particles 1 mark
Question 3 (2 marks)
In a physical change the material can recover its original properties if the change is reversed. In a chemical change new substances are made and this cannot easily be reversed.
• Physical: reversible with original properties 1 mark
• Chemical: new substances 1 mark
Question 4 (3 marks)
In a solid the particles are in fixed positions and vibrate. As the solid melts the particles gain energy, break away from fixed positions and can move around each other while staying close.
• Solid: fixed regular positions, vibrating 1 mark
• Gain energy 1 mark
• Liquid: still close but move around each other 1 mark
Question 5 (3 marks)
In the steam the particles are far apart, but in the liquid they are close together. The same particles occupy a much larger volume, although the mass has not changed.
• Particles far apart in gas 1 mark
• Close together in liquid 1 mark
• Same mass, greater volume 1 mark