A student mixes the same volumes of solutions A and B. The solutions react to form a gas.
The student changes the conditions and records the results.
| Experiment | Temperature in ∘C^\circ\mathrm{C}∘C | Concentration of solution A in mol/dm3\mathrm{mol/dm^3}mol/dm3 | Volume of gas made in the first 20 s in cm3\mathrm{cm^3}cm3 | Final volume of gas in cm3\mathrm{cm^3}cm3 |
|---|---|---|---|---|
| 1 | 20 | 0.20 | 30 | 120 |
| 2 | 30 | 0.20 | 58 | 120 |
| 3 | 20 | 0.40 | 57 | 240 |
All other conditions are kept the same.
Calculate the mean rate of gas production during the first 20 s for Experiments 1 and 2.
Give the unit of rate.
The student wants to increase the rate during the first 20 s without changing the final volume of gas.
Should the student use the conditions in Experiment 2 or the conditions in Experiment 3? Explain your answer.
Use the data and ideas about collisions between particles in your answer.
122 exam-style questions on OCR GCSE Chemistry 5.2 Controlling reactions, covering 5.2.1 Measuring and interpreting rate of reaction, 5.2.2 Factors affecting rate and collision theory, and 5.2.3 Catalysts, activation energy and enzymes. Each one has a worked solution and a mark scheme showing where the marks go.