Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Reversible Reactions and Equilibria
144 practice questions
Topics covered
- Reversibility and dynamic equilibria19 practice questions
- Reversible reactions in a sealed container18 practice questions
- The position of equilibrium20 practice questions
- Changing the pressure19 practice questions
- Changing the temperature19 practice questions
- Adding a catalyst19 practice questions
- The effect of concentration19 practice questions
Practice questions
31–40 of 144
Question 31
1 mark · Normal
Answer and check →Which process below best describes the decomposition of ammonium chloride, when heated in a sealed container?
- A.NH4Cl(s) breaks down into NH3(g) and HCl(g), which cannot escape and can recombine to form NH4Cl(s).
- B.NH4Cl(s) melts into a liquid and cannot return to solid form.
- C.NH4Cl(s) reacts with oxygen to form water and nitrogen gas.
- D.NH4Cl(s) changes into NH3(g) and HCl(g), which leave the container permanently.
Question 32
2 marks · Normal
Answer and see the solution →State two reasons why no substances can escape from a sealed container during a reversible reaction.
Question 33
4 marks · Normal
Answer and see the solution →A student heats ammonium chloride in a sealed test tube. The following reversible reaction occurs:
Answer the following questions about this experiment.
(a)[1 mark]State what is meant by a sealed container in this experiment.
(b)[1 mark]Describe what happens to NH3 and HCl in the sealed container after heating.
(c)[1 mark]Explain why both the forward and reverse reactions occur in this setup.
(d)[1 mark]Explain how equilibrium is reached during the reaction.
Question 34
3 marks · Normal
Answer and see the solution →A sample of solid ammonium chloride, , is heated in a sealed tube. The decomposition reaction is:
Suppose you start with 0.80 mol of in the tube. After reaching equilibrium, 0.32 mol of remains.
Calculate the amount (in mol) of ammonia gas, , present at equilibrium.
Question 35
2 marks · Hard
Answer and see the solution →State two essential features that define a sealed container in the context of reversible reactions.
Question 36
5 marks · Hard
Answer and see the solution →(a)[2 marks]Explain what happens to the forward and backward reaction rates when a reversible reaction first starts in a sealed container.
(b)[2 marks]Describe what is meant by equilibrium in this context.
(c)[1 mark]State one reason why equilibrium can only be reached if the container is sealed.
Question 37
2 marks · Hard
Answer and see the solution →In an experiment, solid ammonium chloride is heated in a sealed tube. Name the two gases that form, and state what happens when they meet in a cooler part of the tube.
Question 38
1 mark · Easy
Answer and see the solution →State what happens to the position of equilibrium if the pressure is increased for a reaction in which the number of moles of gas is greater on the left side of the equation than on the right.
Question 39
3 marks · Easy
Answer and see the solution →The following reversible reaction occurs in a sealed container:
The forward reaction is exothermic.
(a)[1 mark]State whether the position of equilibrium will move to the left or the right if the temperature is increased.
(b)[2 marks]Explain your answer to part (a).
Question 40
2 marks · Easy
Answer and see the solution →Consider the equilibrium reaction in a sealed container:
The forward reaction is exothermic. The system is at equilibrium at 400 K and 2 atm pressure.
Calculate the qualitative effect (increase, decrease or no change) on the amount of at equilibrium if:
(a) the temperature is decreased, but the pressure is kept constant.
(a)[2 marks]State the effect on at equilibrium and explain your answer.