Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Changing the surface area of the reactants
19 practice questions
Practice questions
11–19 of 19
Question 11
3 marks · Normal
Answer and see the solution →A student conducts two experiments: - Experiment 1: 5.0 g of marble chips (large lumps) - Experiment 2: 5.0 g marble powder Both react with identical volumes and concentrations of dilute hydrochloric acid at the same temperature. In Experiment 1, all the marble has reacted in 7 minutes. In Experiment 2, the reaction is complete in 2 minutes.
Calculate the average rate of reaction in grams of marble reacted per minute for: (a) Experiment 1 (b) Experiment 2.
Question 12
3 marks · Normal
Answer and see the solution →A factory grinds solid reactants used in a chemical process into fine powder instead of using large lumps. Explain, with reasons, how and why this affects the rate of the reaction.
Question 13
4 marks · Normal
Answer and see the solution →The table shows the total volume of gas produced over time when excess hydrochloric acid reacts separately with two forms of zinc of the same mass: powder and large granules.
Volume of gas produced (cm³) Time (min) Zinc powder (cm³) Zinc granules (cm³) 0 0 0 1 38 15 2 65 25 3 85 32 4 90 39 5 90 43 6 90 44 (a)[1 mark]Describe the difference in the rate of reaction between the powder and granules during the first 3 minutes.
(b)[1 mark]Give the total volume of gas produced at the end of both reactions.
(c)[1 mark]Explain why both forms of zinc produced the same final volume of gas.
(d)[1 mark]Explain why the reaction with zinc powder is faster.
Question 14
1 mark · Normal
Answer and check →Which change will increase the rate of a reaction between a solid and a liquid most effectively?
- A.Grinding the solid into a powder.
- B.Decreasing the temperature.
- C.Using less of the liquid.
- D.Stirring less frequently.
Question 15
2 marks · Normal
Answer and see the solution →State two factors, other than surface area, that can increase the rate of a reaction between a solid and a liquid.
Question 16
4 marks · Normal
Answer and see the solution →A teacher demonstrates the reaction between 3.0 g of magnesium powder and excess dilute hydrochloric acid in a conical flask. She prepares a second flask with 3.0 g of magnesium ribbon. Both are started at the same time.
(a)[2 marks]Predict which flask will finish producing gas first, and explain your answer.
(b)[2 marks]State the total mass of hydrogen gas produced in each flask. (Give your answer to 2 significant figures.) [M_r(H_2) = 2.0. Ar(Mg) = 24.0] Equation:
Question 17
2 marks · Hard
Answer and see the solution →A student investigates the reaction between magnesium and dilute hydrochloric acid. She uses two samples of magnesium of identical mass: one as a single strip and the other cut into many tiny pieces. State and explain how the rate of reaction will differ between the two samples.
Question 18
5 marks · Hard
Answer and see the solution →A student conducts an experiment to discover how changing the surface area of a solid affects the rate of its reaction with a liquid. She reacts 4.0 g of zinc with 25 cm³ of excess dilute sulfuric acid. She performs the same reaction twice:
(a)[2 marks]Describe a safe method she could use to compare the reaction rate using zinc granules and zinc powder, and state a measurement that would provide evidence for which reaction is faster.
(b)[2 marks]Explain, in terms of particle collisions, why the reaction rate changes when using zinc powder instead of granules.
(c)[1 mark]Suggest one other variable, apart from surface area, that must be kept the same to ensure a fair comparison.
Question 19
2 marks · Hard
Answer and see the solution →Explain, using collision theory, why a powdered solid reacts more quickly with a liquid than the same mass of solid in one lump.