Solutions R and S react to form a precipitate. Two samples of solution R contain the same number of R particles, but one sample has a smaller volume.
Each sample is mixed with the same amount of solution S at the same temperature. The precipitate appears sooner with the smaller sample of solution R.
Which statement explains why?
The smaller volume means fewer R particles must react before the precipitate appears.
The smaller volume gives solution R a larger surface area to volume ratio.
Collisions happen less frequently, but a larger fraction of them is successful.
The reactant particles have less space, so R particles collide with S particles more frequently.
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.