IGCSE Chemistry: Gas Theory Past Papers
Topic 1.1.4: Particle Theory & Gas Laws
Exam Instructions:
- • Answer all questions using particle theory explanations
- • Use scientific terminology: "kinetic energy", "more frequent collisions", "greater force"
- • Show your reasoning step-by-step for full marks
- • Total: 55 marks | Time: 50 minutes
Section A: Gas Law Relationships
Quick-fire questions on pressure, volume, and temperature (6 marks)
What happens to the volume of a gas if the pressure is increased at constant temperature?
[1 mark]What happens to the pressure of a gas if the temperature is increased at constant volume?
[1 mark]What happens to the volume of a gas if the temperature is increased at constant pressure?
[1 mark]A gas at 20°C is heated to 40°C. Does the average speed of the particles double?
[2 marks]If the number of gas particles in a container is doubled (at constant temperature and volume), what happens to the pressure?
[1 mark]Section B: Detailed Particle Explanations
Extended response questions - show your working! (19 marks)
Explain, in terms of particles, why the pressure of a gas increases when it is heated at constant volume.
[4 marks]Explain, in terms of particles, why the volume of a gas decreases when the pressure is increased at constant temperature.
[3 marks]A sealed syringe contains air. When the plunger is pushed in quickly, the temperature of the air increases. Explain why.
[4 marks]Explain why a gas exerts pressure on the walls of its container.
[4 marks]A fixed mass of gas is cooled at constant pressure. Explain, in terms of particles, why the volume decreases.
[4 marks]Section C: Real-World Scenarios
Apply particle theory to everyday situations (28 marks)
A sealed balloon is placed in a freezer. Explain what happens to its volume and why.
[5 marks]A can of deodorant has a warning label: "Do not expose to temperatures above 50°C or pierce." Explain both warnings in terms of particle theory.
[6 marks]A weather balloon is released at sea level (pressure = 100 kPa) with a volume of 2.0 m³. At high altitude, the atmospheric pressure drops to 20 kPa. Predict what happens to the balloon's volume and explain your answer.
[6 marks]Car tire manufacturers recommend checking tire pressure when tires are cold. After a long drive, tire pressure increases. Explain why.
[5 marks]A sealed glass bottle containing air is heated strongly. Explain what might happen and why.
[6 marks]Cambridge IGCSE Chemistry (0620) | Papers 2, 4 & 6 Style Questions
Remember: Temperature in Kelvin = °C + 273 | Pressure × Volume = Constant (at constant T)
Sign In to Keep Going
You've reached the end of the free preview. Sign in — and upgrade to Plus or Pro — to keep going with Chemistry.
Full Access
Unlock all 320 lessons