Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Diffusion in gases
19 practice questions
Practice questions
1–8 of 8 · Easy
Question 1
1 mark · Easy
Answer and see the solution →What is the name given to the process by which the particles of a liquid or gas spread out and mix without stirring?
Question 2
3 marks · Easy
Answer and see the solution →A student places a jar of coloured gas below a jar containing only air and quickly removes the lid between them.
(a)[1 mark]State what will eventually be seen in both jars.
(b)[2 marks]Explain why it takes some time for the colour to spread through both jars, using ideas about particles.
Question 3
2 marks · Easy
Answer and see the solution →At room temperature, particles in a gas travel at about 500 m/s. The laboratory is 6 m long.
Calculate:
(a)[1 mark]How long it would take a particle, travelling in a straight line at this speed, to reach the other end of the laboratory.
(b)[1 mark]Explain why, in reality, it takes much longer for a smell to spread across the laboratory.
Question 4
2 marks · Easy
Answer and see the solution →Explain, using the particle model, why diffusion happens faster in a gas than in a liquid.
Question 5
3 marks · Easy
Answer and see the solution →The table shows how long different gases took to diffuse through air in a set apparatus during an experiment.
Time taken for diffusion of different gases through air. Gas Time to mix fully (seconds) Hydrogen 40 Oxygen 60 Ammonia 35 Carbon dioxide 70 (a)[1 mark]Which gas diffused the fastest?
(b)[1 mark]Which gas diffused the slowest?
(c)[1 mark]Suggest, using particle ideas, why there is a difference in the speed at which these gases diffuse.
Question 6
1 mark · Easy
Answer and see the solution →What do you call the uneven spread of particles before diffusion is complete?
Question 7
3 marks · Easy
Answer and see the solution →Two gases, X and Y, are released at opposite ends of a glass tube. After a short time, a white ring forms closer to the end where gas Y was released.
(a)[1 mark]Which gas, X or Y, diffused faster?
(b)[2 marks]Explain why the white ring appears closer to the Y end.
Question 8
2 marks · Easy
Answer and see the solution →A small bottle of perfume breaks at one end of a corridor 18 metres long. If perfume particles travel randomly at an average speed of 600 m/s, calculate:
(a)[1 mark]The time it would take a perfume particle to reach the other end in a straight line, in seconds.
(b)[1 mark]Explain why the actual time to smell the perfume at the other end is much longer.