1. 1
   A sealed rigid gas cylinder, of fixed volume, is at a temperature of 27 degrees Celsius. The cylinder is then heated to a much higher temperature, while its volume stays exactly the same.

   (a)

   A sealed rigid gas cylinder is at a temperature of 27 degrees Celsius. What is this temperature in kelvin?

   [1 mark]

   • A300 K
   • B27 K
   • C246 K
   • D273 K

   (b)

   The sealed cylinder, of fixed volume, is then heated to a much higher temperature. What happens to the pressure of the gas inside?

   [1 mark]

   • AThe pressure decreases
   • BThe pressure increases
   • CThe pressure stays exactly the same
   • DThe pressure becomes zero

   (c)

   Explain, in terms of the motion of the gas particles, why heating the sealed cylinder at constant volume causes the pressure of the gas to increase.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A sealed syringe contains a fixed mass of gas at a pressure of 100 kPa and a volume of 40 cm3, at constant temperature. The plunger is then pushed in, reducing the volume to 25 cm3, still at the same constant temperature.

   (a)

   The plunger is pushed in until the volume becomes 25 cm3. What is the new pressure of the gas?

   [1 mark]

   • A125 kPa
   • B62.5 kPa
   • C160 kPa
   • D40 kPa

   (b)

   Which graph shape correctly describes how the pressure of this fixed mass of gas varies with its volume, at constant temperature?

   [1 mark]

   • AA straight line showing pressure decreasing at a constant rate as volume increases
   • BA straight line through the origin showing pressure increasing proportionally with volume
   • CA horizontal straight line showing pressure staying constant regardless of volume
   • DA curve showing pressure decreasing as volume increases, following an inverse relationship

   (c)

   Explain, in terms of the motion and collisions of the gas particles, why reducing the volume of the syringe at constant temperature causes the pressure of the gas to increase.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   Scientists are cooling a sample of gas to a very low temperature to study its properties, using a sensor that detects the pressure of the gas due to collisions of its particles with the sensor's surface.

   (a)

   Explain what happens to the motion and kinetic energy of the gas particles as the temperature is reduced, and state the value, in degrees Celsius, of absolute zero, the lowest possible temperature.

   [3 marks]

   (b)

   Describe, in terms of particle collisions, what causes the pressure detected by the gas pressure sensor, and explain, in terms of particle motion, why the pressure of the gas (at constant volume) decreases as the scientists cool it towards a very low temperature.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A factory tests aerosol cans, which carry a printed warning not to expose them to temperatures above 50 degrees Celsius or to puncture them, and separately tests the relationship between the pressure and volume of a gas sample using a syringe apparatus.

   (a)

   Describe an experiment using a gas syringe, a pressure gauge and a set of weights (or a hydraulic press), to investigate how the pressure of a fixed mass of gas varies with its volume at constant temperature, explaining how a graph of the results would be used to confirm that pressure x volume = constant, and calculate the volume of the gas at a pressure of 300 kPa, given that at a pressure of 120 kPa its volume was 50 cm3 (at the same constant temperature).

   [6 marks]

   (b)

   Explain, in terms of the kinetic particle model, why an aerosol can (a sealed container of fixed volume) carries a printed warning not to expose it to temperatures above 50 degrees Celsius, describing what happens to the particles of the gas inside the can as its temperature rises, and why this could eventually cause the can to fail or burst.

   [6 marks]

   Total for question 4: 12 marks

End of questions