Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Physical Chemistry
442 practice questions
Topics covered
Practice questions
61–70 of 183 · Easy
Question 61
3 marks · Easy
Answer and see the solution →The reaction between powdered iron and dilute sulfuric acid produces hydrogen gas.
(a)[1 mark]State what particles must do for a reaction to take place according to collision theory.
(b)[1 mark]Name the term for the minimum amount of energy particles need to react when they collide.
(c)[1 mark]Explain why the reaction slows down as the acid is gradually used up.
Question 62
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 63
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 64
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 65
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 66
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 67
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 68
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 69
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 70
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.