1. 1
   A metalworker heats a solid block of tin in a furnace until it turns into a liquid.

   (a)

   Which term describes this change of state from solid to liquid?

   [1 mark]

   • Amelting
   • Bboiling
   • Cevaporating
   • Dcondensing

   (b)

   While the tin is melting at its melting point, the furnace continues supplying heat energy to the metal. What happens to the temperature of the tin during the melting process?

   [1 mark]

   • AIt decreases steadily
   • BIt increases steadily
   • CIt stays constant
   • DIt increases then decreases

   (c)

   Describe, in terms of the arrangement and motion of particles, what happens to the tin as it changes from a solid to a liquid.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A cook leaves an open pan of water simmering gently on a stove, and steam is seen rising continuously from the surface of the water even though the water is not yet boiling.

   (a)

   Which process best describes water turning to vapour at the surface of the pan below its boiling point?

   [1 mark]

   • Afreezing
   • Bboiling
   • Cmelting
   • Devaporation

   (b)

   As water evaporates from the surface of the pan, what happens to the temperature of the remaining water, assuming no further heating from the stove?

   [1 mark]

   • AIt increases
   • BIt decreases
   • CIt stays exactly the same
   • DIt doubles

   (c)

   Explain, in terms of particles, why evaporation causes cooling of the remaining liquid.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A historian is researching an old ice-house used before refrigeration existed, where large blocks of ice were stored to keep food cold through the summer.

   (a)

   Explain why heating an ice block will change the energy stored within it and describe what happens to this energy as the ice slowly warms up, melts, and the resulting water is then heated further.

   [3 marks]

   (b)

   A 4.0 kg block of ice, already at 0°C, is fully melted using 1,336,000 J of energy. Explain why the equation ΔQ = m × c × ΔT cannot be used here, then calculate the specific latent heat of fusion of the ice using specific latent heat = energy supplied ÷ mass, and state the unit of your answer.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A technician is investigating the specific heat capacity of two unknown solid blocks, one metal and one plastic, of equal mass, by heating each with an identical immersion heater and recording a temperature-time graph for each.

   (a)

   Explain what is meant by specific heat capacity, describe how the technician could use this practical set-up to determine the specific heat capacity of each block, and explain how the temperature-time graphs of the two blocks would differ if the metal has a much lower specific heat capacity than the plastic.

   [6 marks]

   (b)

   The metal block has a mass of 0.5 kg and a specific heat capacity of 900 J/kg°C. The heater supplies 60 W of power. Calculate the time needed to raise the temperature of the metal block from 20°C to 80°C, and evaluate one source of experimental error in this method that could make the calculated specific heat capacity too high, explaining how it could be reduced.

   [6 marks]

   Total for question 4: 12 marks

End of questions