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The student uses dilute hydrochloric acid at a temperature of 50°C. The student measures the total loss in mass of the reaction mixture every 25 seconds for 150 seconds. Figure 7.1 shows a graph of the results. 1.10 1.00 0.90 aa 0.80 0.70 7 0.60 total loss in mass/g I 0.50 — 0.40 = 0.30 0.20 — 0.10 = 0.00 0 25 50 75 10...
See it on the paper →The student repeats the experiment using dilute hydrochloric acid at a temperature of 30°C. All other conditions remain the same. Describe how the shape of the graph in Figure 7.1 would be different at 30°C.
See it on the paper →Identify which concentration of aqueous sodium thiosulfate gave the fastest reaction.
See it on the paper →Identify the least concentrated solution of aqueous sodium thiosulfate. Explain your answer.
See it on the paper →Explain your answer using collision theory.
See it on the paper →The reaction between dilute sulfuric acid and copper oxide is faster when more concentrated acid is used. Explain why, using collision theory.
See it on the paper →time = minutes State the time when the reaction stops. (i)
See it on the paper →This question was generally well answered with candidates referring to kinetic energy and frequency and effectiveness of collisions. However, few candidates referred to fewer particles having the required activation energy.
— Examiner report, February/March 2025, 0654/42 Q6(c) (Cambridge)
Explanations of the increased rate of reaction between magnesium and hot water often referred to the increased energy of water molecules. Credit was given when candidates inferred that the rate of reaction increases because of the increased rate of collision between particles. A few realised that the main cause of the increase in the rate of reaction is the greater number of particles achieving th...
— Examiner report, October/November 2022, 0654/41 Q5(c)(i) (Cambridge)
Some candidates correctly explained that the rate of reaction increased when powdered magnesium is used because of the increased rate of collision between particles. Others referred to more collisions and were not given credit. Some also correctly stated that a greater surface area of magnesium is exposed to collision by water particles.
— Examiner report, October/November 2022, 0654/41 Q5(c)(ii) (Cambridge)
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Calculate the average rate of the reaction during the first two minutes of the experiment. rate = cm 3 / minute
Student 1 repeats their experiment at a lower temperature. The reaction is slower. Explain why the reaction is slower, using collision theory.
See it on the paper →Which statements explain why the rate of this reaction increases at higher temperatures?
See it on the paper →The students did the experiments at 20 °C. State how the rate of reaction will change if they do the experiments again at 40 °C. Explain your answer using ideas about collisions between particles.
See it on the paper →Fig. 11.2 shows the energy level diagram for the reaction to make sulfur trioxide. energy reactants products progress of reaction Fig. 11.2 Draw and label on Fig. 11.2: • the energy change in the reaction ,
See it on the paper →Water reacts with magnesium metal. The reaction is very slow. The reaction is faster if hot water is used. Explain why. Use ideas about collisions between particles.
See it on the paper →The reaction between water and magnesium is faster if powdered magnesium is used instead of strips of magnesium. Explain why. Use ideas about collisions between particles.
See it on the paper →The rate of reaction is decreased by decreasing the concentration of the hydrochloric acid. State two other ways of decreasing the rate of this reaction.
See it on the paper →The rate of the reaction can be increased by increasing the concentration of the dilute hydrochloric acid. Explain why. Use ideas about collisions between particles.
See it on the paper →In all three experiments the student keeps the same: volume of dilute hydrochloric acid concentration of dilute hydrochloric acid size pieces of zinc. • • • State one variable that could have been changed from experiment 1 to produce the results in experiment 2. Explain your answer. variable changed explanation
See it on the paper →Lead reacts very slowly with dilute sulfuric acid. State two ways of increasing the rate of reaction between lead and dilute sulfuric acid.
See it on the paper →Ammonia is used in the manufacture of some fertilisers. Ammonia is made in the Haber process. ammonia nitrogen + hydrogen Fig. 2.1 shows the percentage of ammonia made using different conditions of temperature and pressure. 100 200 °C 80 400 °C 60 percentage of ammonia made 40 600 °C 20 0 0 100 200 300 400 500 pressure...
See it on the paper →Use ideas about colliding particles to explain the shape of the graph.
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