Pearson Edexcel International GCSE (9–1) · PHYSICS · Section
The energy involved in change of state
17 practice questions
Practice questions
1–10 of 10 · Normal
Question 1
1 mark · Normal
Answer and check →Which statement best describes what happens during the boiling of a liquid?
- A.The temperature increases rapidly and then stops.
- B.The added energy is used to increase the speed of the particles.
- C.The energy supplied is used to overcome the forces between the particles, so temperature remains constant.
- D.The liquid evaporates only from the surface, with the temperature increasing all the time.
Question 2
3 marks · Normal
Answer and see the solution →Describe a practical method to obtain a temperature–time graph showing the change of state from solid to liquid for a substance such as naphthalene. Include details on how to make the experiment as accurate as possible.
Question 3
1 mark · Normal
Answer and see the solution →Why is it important to use a water bath instead of a direct flame when heating substances like naphthalene to study their change of state?
Question 4
4 marks · Normal
Answer and see the solution →A student heats a sample of solid wax in a beaker and records the temperature every minute as it melts and becomes a liquid.
(a)[2 marks]Describe what happens to the temperature of the wax just as it is melting, even though heating continues.
(b)[2 marks]Explain why the temperature behaves this way during melting.
Question 5
3 marks · Normal
Answer and see the solution →An electric heater supplies 200 W to a block of ice at -10°C. The ice has a mass of 0.5 kg. The specific heat capacity of ice is 2100 J/kg°C. Calculate the time needed to raise the temperature of the ice to 0°C.
Question 6
4 marks · Normal
Answer and see the solution →You are asked to investigate the melting of naphthalene in the laboratory.
(a)[2 marks]List two pieces of equipment you need to measure the temperature at fixed time intervals as naphthalene melts.
(b)[2 marks]Explain one safety precaution you should take when carrying out this investigation.
Question 7
3 marks · Normal
Answer and see the solution →Explain, in terms of particles, what happens to the thermal energy and movement of particles in a pure substance as it melts at its melting point.
Question 8
4 marks · Normal
Answer and see the solution →A group of students heated a small sample of solid naphthalene. They recorded the temperature every minute for 15 minutes. The melting point of naphthalene is 80°C. Their results are shown below.
Temperature readings for naphthalene Time (min) Temperature (°C) 0 40 2 55 4 69 6 80 8 80 10 80 12 86 15 93 Use the table to answer the questions.
(a)[1 mark]For how many minutes did the naphthalene remain at 80°C?
(b)[2 marks]Explain why the temperature stayed at 80°C for this time even though the substance was being heated.
(c)[1 mark]What was happening to the naphthalene during this period?
Question 9
1 mark · Normal
Answer and check →Which statement best describes the change in energy as a substance boils at its boiling point?
- A.The substance's temperature keeps increasing as it boils.
- B.The supplied energy is used to break the bonds between particles.
- C.The energy supplied is lost to the surroundings.
- D.The energy is used to increase the mass of the liquid.
Question 10
3 marks · Normal
Answer and see the solution →A mixture of ice and water is kept at 0°C. Explain, using ideas about energy and particles, what happens to the temperature when more ice melts.