Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Principles of Chemistry
991 practice questions
Topics covered
- States of Matter102 practice questions
- Elements, Compounds and Mixtures69 practice questions
- Atomic Structure108 practice questions
- The Periodic Table103 practice questions
- Chemical Formulae, Equations and Calculations Part 119 practice questions
- Chemical Formulae, Equations and Calculations Part 2144 practice questions
- Ionic Bonding143 practice questions
- Covalent Bonding68 practice questions
- Metallic Bonding19 practice questions
- Electrolysis198 practice questions
Practice questions
41–50 of 991
Question 41
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 42
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 43
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 44
1 mark · Easy
Answer and see the solution →What do you call the uneven spread of particles before diffusion is complete?
Question 45
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 46
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.
Question 47
2 marks · Normal
Answer and see the solution →Explain what is meant by diffusion in gases, using the idea of particles.
Question 48
4 marks · Normal
Answer and see the solution →(a)[1 mark]Figure 1 shows an apparatus used to investigate the diffusion of bromine gas.
Apparatus for diffusion of bromine gas State what you would observe if the lid between the two gas jars is removed.
(b)[2 marks]Explain why the observation described in (a) happens, using ideas about particles.
(c)[1 mark]Suggest why the bromine gas eventually spreads throughout both jars.
Question 49
3 marks · Normal
Answer and see the solution →Two cotton wool plugs, one soaked in concentrated ammonia solution and the other in concentrated hydrochloric acid, are placed at opposite ends of a long glass tube.
After some time, a white ring of ammonium chloride forms closer to the hydrochloric acid end.
Explain why the white ring forms closer to the hydrochloric acid end rather than in the middle. Use ideas about particles and diffusion.
Question 50
1 mark · Normal
Answer and check →Which statement best describes diffusion in gases?
- A.Particles move from a region of low concentration to high concentration.
- B.Particles remain completely still until energy is added.
- C.Particles move from a region of high concentration to low concentration.
- D.Particles only move if they are liquids.