Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Rates of Reaction
164 practice questions
Topics covered
- Experiments to measure the rate of reaction19 practice questions
- Explaining what's happening19 practice questions
- Changing the surface area of the reactants19 practice questions
- Changing the concentration of the reactants19 practice questions
- Changing the pressure on the reaction19 practice questions
- What are catalysts?19 practice questions
- How does a catalyst work?20 practice questions
- Catalysts in industry19 practice questions
Practice questions
11–20 of 68 · Easy
Question 11
2 marks · Easy
Answer and see the solution →Explain, using collision theory, why a reaction between magnesium ribbon and excess hydrochloric acid is faster at the start than at the end.
Question 12
3 marks · Easy
Answer and see the solution →A student observes the reaction between excess sodium carbonate and dilute hydrochloric acid. The table shows the concentration of acid over time.
Concentration of acid during reaction Time (min) Acid concentration (mol/dm³) 0 1.00 1 0.85 2 0.70 3 0.60 4 0.59 5 0.59 (a)[1 mark]Between which two times was the reaction fastest? Explain your answer.
(b)[1 mark]State why the reaction gradually slows down as shown in the table.
(c)[1 mark]According to collision theory, what needs to happen for acid particles to react with sodium carbonate?
Question 13
1 mark · Easy
Answer and see the solution →Name the theory that explains how the frequency and energy of collisions affect the rate of chemical reactions.
Question 14
3 marks · Easy
Answer and see the solution →A student investigates how fast sodium reacts with water to produce hydrogen gas at room temperature.
(a)[1 mark]State what must happen to sodium and water particles for this reaction to occur.
(b)[1 mark]According to collision theory, what is a successful collision?
(c)[1 mark]Explain why the reaction rate might change during the experiment.
Question 15
2 marks · Easy
Answer and see the solution →A reaction in a beaker starts with 50 reacting particles per cm³. After a few minutes, only 10 reacting particles per cm³ remain.
Calculate the percentage decrease in the number of reacting particles per cm³ during the reaction.
Question 16
2 marks · Easy
Answer and see the solution →In a reaction, there are 40 effective collisions per minute at the start. After some time, the number of effective collisions drops to 12 per minute.
Calculate how many times faster the reaction was at the start compared to later. Give your answer as a number.
Question 17
1 mark · Easy
Answer and see the solution →State what happens to the rate of reaction when a solid reactant is broken into smaller pieces, keeping all other conditions the same.
Question 18
3 marks · Easy
Answer and see the solution →A student compares the reaction between calcium carbonate and hydrochloric acid using two forms of calcium carbonate: large lumps and powdered. All other conditions are kept the same.
(a)[1 mark]State which form will react faster.
(b)[2 marks]Explain why this form reacts faster.
Question 19
2 marks · Easy
Answer and see the solution →Two pieces of magnesium ribbon, A and B, have the same mass. Ribbon B is cut into 4 equal shorter pieces. Both are added to separate beakers with the same volume and concentration of hydrochloric acid at the same temperature.
Ribbon A takes 200 seconds to finish reacting. Estimate how the time taken for Ribbon B to finish reacting compares to A, and explain your reasoning.
Question 20
2 marks · Easy
Answer and see the solution →Explain why a reaction between a solid and a liquid is faster when the solid is ground into a fine powder rather than used as one large lump.