1. 1
   A sealed syringe contains a fixed mass of gas at a pressure of 150 kPa and a volume of 24 cm3, at a constant temperature of 20 degrees Celsius.

   (a)

   What is this temperature in kelvin?

   [1 mark]

   • A293 K
   • B253 K
   • C20 K
   • D546 K

   (b)

   The plunger is pushed in, reducing the volume to 16 cm3 at the same temperature. What is the new pressure of the gas?

   [1 mark]

   • A100 kPa
   • B150 kPa
   • C225 kPa
   • D3600 kPa

   (c)

   The sealed syringe is then heated at constant volume. Explain, in terms of the motion of the gas particles, why the pressure of the gas increases as its temperature rises.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   An immersion heater supplies 900 J of energy to a 0.50 kg block of aluminium, initially at 20 degrees Celsius, over a short time. The specific heat capacity of aluminium is 900 J/(kg degC).

   (a)

   What is the temperature rise of the block?

   [1 mark]

   • A0.5 degC
   • B2.0 degC
   • C450 degC
   • D1620 degC

   (b)

   What is the final temperature of the block?

   [1 mark]

   • A2.0 degC
   • B18 degC
   • C20 degC
   • D22 degC

   (c)

   Describe how an experiment could be carried out to measure the specific heat capacity of the block of aluminium using an electrical heater.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A beaker of solid ice at -10 degrees Celsius is heated steadily on a hot plate. Its temperature is monitored with a thermometer throughout: the ice is observed to melt, and the resulting water is then heated further until it reaches its boiling point and boils away as steam.

   (a)

   State the melting point and the boiling point of water at standard atmospheric pressure, and describe what happens to the temperature reading while the ice is melting, even though the hot plate continues to supply energy.

   [3 marks]

   (b)

   Explain, in terms of the energy and behaviour of the particles, the difference between boiling and evaporation.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A cook places a stainless steel saucepan of soup on a gas hob. The saucepan has a solid plastic handle. The metal base and sides of the pan quickly become too hot to touch, while the plastic handle stays much cooler for longer, even though both are in contact with the hot pan.

   (a)

   Explain, in terms of particles, why the metal parts of the pan conduct thermal energy well, while the plastic handle conducts thermal energy poorly.

   [6 marks]

   (b)

   Describe, in terms of the arrangement, separation and motion of the particles, the differences between the pan's metal in the solid state and in the molten (liquid) state, and explain, in terms of energy transfer, why the temperature of the molten metal does not fall while it is solidifying (freezing), even though it continues to lose thermal energy to its surroundings.

   [6 marks]

   Total for question 4: 12 marks

5. 5
   A materials scientist compares three sealed containers of the same substance: one containing it as a solid, one as a liquid and one as a gas, all at different temperatures.

   (a)

   In which state are the particles arranged in a fixed, regular pattern and only vibrate about fixed positions?

   [1 mark]

   • ASolid
   • BLiquid
   • CGas
   • DSolid and liquid

   (b)

   In which state are the particles typically furthest apart, and moving fastest, compared with the other two states?

   [1 mark]

   • ASolid
   • BGas
   • CLiquid
   • DSolid and gas

   (c)

   State two ways in which the particles of a gas differ from the particles of a liquid of the same substance, in terms of their separation and motion.

   [2 marks]

   Total for question 5: 4 marks

6. 6
   A civil engineer building a steel railway bridge leaves small expansion gaps between adjoining sections of the steel track, and fits the bridge with expansion joints that allow small horizontal movements.

   (a)

   Why does the engineer leave gaps between sections of the steel track?

   [1 mark]

   • ATo save on the amount of steel used
   • BTo reduce the mass of the bridge
   • CTo allow the steel to expand on hot days without buckling
   • DTo make the track easier to lay

   (b)

   A sealed glass bottle, completely full of water, is placed in a freezer and the water freezes solid. What is most likely to happen?

   [1 mark]

   • ANothing, since water does not change volume when it freezes
   • BThe bottle shrinks slightly
   • CThe water contracts, leaving a gap at the top
   • DThe bottle may crack, because water expands unusually as it freezes

   (c)

   Explain, in terms of the motion and arrangement of particles, why solids generally expand by a much smaller amount than gases do for the same rise in temperature.

   [2 marks]

   Total for question 6: 4 marks

7. 7
   A room is heated by an electric panel heater mounted low down on one wall, near the floor. A student holds a lit incense stick near the ceiling on the opposite side of the room and observes the smoke drifting slowly across the room and then downward.

   (a)

   Explain, in terms of density changes, why the air heated by the panel heater rises upward, setting up a convection current in the room.

   [3 marks]

   (b)

   Using the idea of a convection current, describe the path the smoke from the incense stick is likely to follow as it circulates around the room, and explain why the panel heater is more effective at heating the whole room when mounted low down near the floor rather than high up near the ceiling.

   [4 marks]

   Total for question 7: 7 marks

8. 8
   A homeowner is choosing between two designs of outdoor water tank for a garden irrigation system: one painted matt (dull) black, and one painted shiny silver. Both tanks are identical in size and are placed outdoors in direct sunlight during the day, and both are also used to store hot water overnight.

   (a)

   Describe and explain the effect of the tank's surface colour and texture on how much infrared radiation it absorbs and emits, and use this to predict, with a reason, which tank would reach a higher temperature during the day in direct sunlight.

   [6 marks]

   (b)

   At night, both tanks are full of hot water and there is no sunlight. Using the idea that an object at constant temperature must transfer energy away at the same rate it receives energy, explain which tank would be better at keeping its water warm overnight, and suggest one practical design change to either tank that would help it lose thermal energy more slowly overall, considering conduction and convection as well as radiation.

   [6 marks]

   Total for question 8: 12 marks

End of questions