Powdered calcium carbonate reacts faster with hydrochloric acid than the same mass of large lumps.
Which explanation is correct?
The powder particles have more energy, so more collisions are successful.
The powder lowers the activation energy, so more collisions are successful.
The powder contains more calcium carbonate, so more collisions happen.
The powder has a larger surface area to volume ratio, so collisions are more frequent.
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.