A student mixes two colourless solutions. The mixture slowly turns blue, and the student times how long it takes to reach the same shade of blue each time.
In the first run, the shade is reached after 96 s. In a second run, only the concentration of the first solution is changed, and the shade is reached after 24 s.
For this reaction, the rate increases in the same ratio as the concentration of the first solution.
How does the concentration of the first solution in the second run compare with the first run?
It is 3 times as concentrated
It is one quarter as concentrated
It is 16 times as concentrated
It is 4 times as concentrated
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.