Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Physical Chemistry
442 practice questions
Topics covered
Practice questions
311–320 of 442
Question 311
4 marks · Normal
Answer and see the solution →The table shows the number of blue and yellow squares in a sealed container at intervals during a reversible reaction.
Time (s) Number of blue squares Number of yellow squares 0 64 0 1 48 16 2 36 28 3 27 37 4 20 44 (a)[1 mark]Describe the trend in the number of blue squares over time.
(b)[1 mark]Describe how the number of yellow squares changes over time.
(c)[1 mark]Predict what will happen to the numbers of blue and yellow squares if the reaction continues.
(d)[1 mark]Explain how these trends are related to reversible reactions reaching equilibrium.
Question 312
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 313
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 314
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 315
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 316
2 marks · Hard
Answer and see the solution →State two essential features that define a sealed container in the context of reversible reactions.
Question 317
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 318
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 319
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 320
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).