Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Physical Chemistry
442 practice questions
Topics covered
Practice questions
151–160 of 442
Question 151
4 marks · Normal
Answer and see the solution →A reaction between excess zinc and dilute sulfuric acid is carried out in a conical flask. The total volume of hydrogen gas produced is measured.
(a)[1 mark]State one way the rate of this reaction could be increased without changing the temperature.
(b)[3 marks]Explain your answer to part (a) using collision theory.
Question 152
3 marks · Normal
Answer and see the solution →A student reacts marble chips (calcium carbonate) with dilute hydrochloric acid in a beaker. At the start, there are 60 acid particles per cm³ in the solution. Every second, about 18 of these particles collide with the marble chips. Only 5 of these collisions have enough energy to result in a reaction and are called successful collisions.
(a)[2 marks]Calculate the percentage of collisions that are successful each second at the start of the reaction.
(b)[1 mark]Explain, using collision theory, what happens to the rate of reaction as the number of acid particles falls during the experiment.
Question 153
2 marks · Hard
Answer and see the solution →The reaction between excess potassium carbonate and dilute nitric acid is observed to slow down over time. Explain, using collision theory, why this happens.
Question 154
5 marks · Hard
Answer and see the solution →A student compares the rates of reaction between two samples of marble chips (calcium carbonate) and dilute phosphoric acid at room temperature. In experiment 1, large marble chips are used; in experiment 2, the marble chips are crushed into a fine powder. The same mass of marble and the same volume of acid are used in both experiments.
(a)[2 marks]State which experiment will have the faster initial rate of reaction, and give a reason using collision theory.
(b)[1 mark]Draw a suitable diagram to show the difference in surface area between the marble chips in experiment 1 and the powder in experiment 2.
(c)[2 marks]Explain, using collision theory, why the reaction stops even though there is excess marble in both experiments.
Question 155
2 marks · Hard
Answer and see the solution →A sealed flask contains hydrogen peroxide decomposing into water and oxygen gas. The reaction rate decreases over time. Use collision theory to explain why the rate gets slower, even though the temperature stays the same.
Question 156
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 157
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 158
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 159
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.
Question 160
3 marks · Easy
Answer and see the solution →The graph below shows how the mass of carbon dioxide produced changes over time during the reaction between excess hydrochloric acid and two forms of calcium carbonate, both of the same mass.
Graph: Mass of CO2 produced (g) vs. Time (minutes) (a)[1 mark]Which form of calcium carbonate reacts faster? Give evidence from the graph.
(b)[1 mark]State the total mass of carbon dioxide produced at the end of both reactions.
(c)[1 mark]Explain why both forms produce the same final mass of carbon dioxide.