Pearson Edexcel International GCSE (9–1) · PHYSICS · Chapter
Ideal Gas Molecules
70 practice questions
Topics covered
Practice questions
31–35 of 35 · Normal
Question 31
1 mark · Normal
Answer and see the solution →A student writes this formula for converting celsius to kelvin:
T_kelvin = T_celsius + 273Question 32
5 marks · Normal
Answer and see the solution →A student places a glass bottle full of air with a tight lid in a refrigerator. The air inside was initially at room temperature (22 °C) and atmospheric pressure (100 kPa). After several hours, the bottle’s temperature has dropped to 4 °C.
(a)[2 marks]Explain, using the idea of gas particles, what happens to the pressure of the air in the bottle as it cools.
(b)[3 marks]Calculate the final pressure of the air in the bottle, in kPa. Give your answer to 2 significant figures. (You must use the Kelvin scale for temperature.)
Question 33
5 marks · Normal
Answer and see the solution →A fixed mass of gas in a metal cylinder is at a pressure of 120 kPa and a temperature of 300 K. The gas is then compressed while being heated, so that its temperature rises to 360 K and its volume halves.
(a)[1 mark]Write down the gas law equation that links pressure, volume, and temperature for a fixed mass of gas.
(b)[3 marks]Calculate the final pressure of the gas, in kPa.
(c)[1 mark]Explain why the pressure in the cylinder increases, even though the gas is heated.
Question 34
5 marks · Normal
Answer and see the solution →A balloon filled with helium has a pressure of 105 kPa and a volume of 1.8 litres at 25°C. The balloon is taken outside where the temperature drops to 5°C, but the pressure remains constant.
(a)[2 marks]Explain what happens to the average kinetic energy of the helium molecules as the temperature changes. Your answer should refer to the temperature in Kelvin.
(b)[3 marks]Calculate the new volume of the balloon at 5°C. Give your answer to 2 significant figures.
Question 35
5 marks · Normal
Answer and see the solution →The graph below shows how the pressure of a fixed mass of gas at constant volume varies with temperature:
Graph of pressure vs. temperature (°C) for a fixed volume of gas (a)[2 marks]Determine the temperature at which the pressure of the gas would reach zero according to the graph.
(b)[3 marks]Explain what this value represents physically, and how it is linked to the kinetic energy of the gas molecules.