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
21–30 of 63 · Normal
Question 21
2 marks · Normal
Answer and see the solution →A reversible reaction is shown below: The forward reaction is exothermic. Explain what will happen to the position of equilibrium if the temperature is increased.
Question 22
3 marks · Normal
Answer and see the solution →Hydrogen iodide is formed in the reversible reaction: The forward reaction is endothermic. A closed container starts with 0.50 mol of hydrogen, 0.50 mol of iodine, and no hydrogen iodide. The mixture is allowed to reach equilibrium. State and explain what will happen to the amount of hydrogen iodide present at equilibrium if the pressure is doubled (assume temperature is kept constant and all substances are gases, with equal volumes occupied).
Question 23
1 mark · Normal
Answer and see the solution →For the equilibrium reaction:
The forward reaction is exothermic. What will happen to the concentration of PCl5 if the temperature is increased at constant pressure?
- A.It will increase.
- B.It will decrease.
- C.It will stay the same.
- D.It will fluctuate.
Question 24
2 marks · Normal
Answer and see the solution →A reversible reaction occurs in a sealed container: . The forward reaction is exothermic.
State what happens to the position of equilibrium if:
(a)[1 mark]the temperature is increased.
(b)[1 mark]the pressure is increased.
Question 25
4 marks · Normal
Answer and see the solution →Consider the following equilibrium established in a sealed container:
The forward reaction is endothermic.
(a)[2 marks]State and explain what will happen to the position of equilibrium if the temperature is decreased.
(b)[2 marks]State and explain what will happen to the position of equilibrium if the pressure is increased.
Question 26
3 marks · Normal
Answer and see the solution →The following equilibrium is established in a sealed container at constant temperature:
The forward reaction is exothermic.
The system is at equilibrium with the following amounts:
Substance Amount (mol) D 0.80 E 1.60 F 0.60 G 0.60 (a)[3 marks]The pressure on the system is increased. Predict, with a calculation, which direction the equilibrium will shift. Show your working.
Question 27
2 marks · Normal
Answer and see the solution →State why changing the pressure affects only equilibria involving gases, and only when the numbers of gaseous molecules on each side of the equation are different.
Question 28
4 marks · Normal
Answer and see the solution →The following reaction takes place in a closed container:
(a)[1 mark]State the total number of moles of gas on each side of this equation.
(b)[3 marks]The pressure of the system is increased. Predict and explain the direction in which the equilibrium will shift.
Question 29
3 marks · Normal
Answer and see the solution →The reaction below is allowed to reach equilibrium in a sealed container:
Explain, using the number of moles of gas, what will happen to the position of equilibrium if the pressure is decreased.
Question 30
4 marks · Normal
Answer and see the solution →Consider the following data collected for this equilibrium reaction:
Condition % M(g) % N(g) % Q(g) Low pressure 40 40 20 High pressure 45 45 10 (a)[1 mark]What is the total number of moles of gas on each side of the equation?
(b)[2 marks]Describe the effect that increasing pressure has on the amounts of M(g), N(g), and Q(g).
(c)[1 mark]Explain your answer to (b) in terms of the number of gas molecules.