0653.C6.2.02 — State that a catalyst increases the rate of a reaction and is unchanged at the end of a reaction: past paper questions
Real questions on 0653.c6.2.02 — state that a catalyst increases the rate of a reaction and is unchanged at the end of a reaction
The newest 20 of 20 written questions. Open one to see it on the real paper.
- 0653/32 · May/June 2025 · Q6d[2]
Describe what is meant by a catalyst.
See it on the paper → - 0653/62 · October/November 2024 · Q1b(ii)[1]
Consider one source of error identified in (b)(i). Describe one improvement in the procedure to minimise this error.
See it on the paper → - 0653/62 · October/November 2024 · Q2a(i)[1]
Explain why it is important to stir the mixture of H and distilled water in step 4.
See it on the paper → - 0653/62 · October/November 2024 · Q2a(ii)[2]
°C °C 50 70 40 60 30 50 Fig. 2.1 shows the reading on the thermometer for the highest temperature reached for 1.0 g and for 2.5 g of H. highest temperature with 2.5 g of H highest temperature with 1.0 g of H Fig. 2.1 Record in Table 2.1 these temperatures to the nearest 0.5 °C. Table 2.1 mass of H / g temperature of di...
See it on the paper → - 0653/62 · May/June 2024 · Q2a(i)[1]
Explain why it is difficult to identify the positive ion (cation) present in solution X using the flame test in test 4. (i)
See it on the paper → - 0653/62 · May/June 2024 · Q2a(ii)[1]
Explain why the student does not use a yellow Bunsen burner flame for the flame test. (ii) ,
See it on the paper → - 0653/62 · May/June 2024 · Q2b[1]
Solution X is blue. In test 3, the precipitate appears to be blue. Describe what the student does to confirm the precipitate is white and not blue.
See it on the paper → - 0653/62 · May/June 2024 · Q2c[2]
Identify the negative ion (anion) present in solution X. State which test you use to make this identification. negative ion is
See it on the paper → - 0653/62 · May/June 2024 · Q2d[2]
Solution X contains Cu 2+ ions. Describe the observations made by the student. The student adds aqueous ammonia to solution X until the ammonia is in excess. ,
See it on the paper → - 0653/62 · May/June 2024 · Q3[7]
When an aqueous salt solution is left in an open container, the mass of the solution decreases. This is because some of the water evaporates. Plan an investigation to determine the relationship between the concentration of salt solution and the rate of evaporation of water from the salt solution. You are provided with:...
See it on the paper → - 0653/62 · May/June 2024 · Q4a(i)[2]
Record in Table 4.1 the two temperatures for time t = 60 s. Table 4.1 time t / s temperature θ A (without a lid) / °C temperature θ B (with a lid) / °C 0 84.0 79.0 30 81.0 77.5 90 75.5 74.0 120 73.0 77.0 150 71.0 71.5 180 69.0 70.0 60
See it on the paper → - 0653/62 · May/June 2024 · Q4a(ii)[1]
Circle the anomalous result in Table 4.1. ,
See it on the paper → - 0653/12 · October/November 2023 · Q18[1]
In which row do all of the changes shown increase the rate of reaction?
See it on the paper → - 0653/61 · October/November 2023 · Q2b(ii)[1]
Explain the importance of step 3 in the procedure.
See it on the paper → - 0653/61 · October/November 2023 · Q2b(iii)[1]
Suggest one source of uncertainty in the measurement of the reaction time.
See it on the paper → - 0653/61 · October/November 2023 · Q2b(iv)[2]
Fig. 2.1 shows the stop-watch readings for 5 mm and 25 mm lengths of magnesium ribbon. 0:30.09 0:30.69 5 mm length 25 mm length Fig. 2.1 Record in Table 2.1 the reaction times in Fig. 2.1 to the nearest second. Table 2.1 length of magnesium ribbon / mm reaction time / s rate of reaction in mm / s 10 31 0.32 15 29 0.52...
See it on the paper → - 0653/61 · October/November 2023 · Q2b(v)[1]
Calculate the rate of reaction for the 5 mm and 25 mm lengths of magnesium ribbon. Use the equation shown. rate of reaction = length of magnesium ribbon reaction time Record your values in Table 2.1.
See it on the paper → - 0653/61 · October/November 2023 · Q2b(vi)[3]
On the grid, plot a graph of the rate of reaction (vertical axis) against the length of magnesium ribbon.
See it on the paper → - 0653/61 · October/November 2023 · Q2b(vii)[1]
Draw the line of best fit.
See it on the paper → - 0653/12 · October/November 2022 · Q18[1]
Which row shows the conditions that produce the highest rate of reaction?
See it on the paper →
What examiners said
The idea that a catalyst speeds up the rate of reaction was stated by many candidates. The idea that the catalyst is unchanged at the end of the reaction, was only given by some candidates. The definition of a catalyst as being a biological molecule, as in an enzyme, was frequently seen. This was not accepted because an enzyme is an example of a catalyst but there are many other chemicals which ar...
— Examiner report, May/June 2025, 0653/32 Q6(d) (Cambridge)
Step 3 referred to the use of a glass rod to keep the magnesium under the surface of the acid. Strong responses related the idea that this brought the whole of the surface area of the magnesium into contact with the acid. Weaker responses tended to repeat/rewrite the information given in the stem, e.g. ‘this keeps the magnesium submerged’.
— Examiner report, October/November 2023, 0653/61 Q2(b)(ii) (Cambridge)
The measurement of the (chemical) reaction time depended on two factors: the student’s judgment of the end of the reaction, and the student’s reaction time in stopping the stop-watch. Both of these were accepted. Unqualified statements such as ‘human error’ or ‘the student may have made a mistake’ were not accepted.
— Examiner report, October/November 2023, 0653/61 Q2(b)(iii) (Cambridge)
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