In an industrial process, a solid reacts with a gas. The solid is supplied as cubes with sides of 12 mm.
Each cube is cut, without any solid being lost, into identical smaller cubes. The surface area to volume ratio of each smaller cube is 2.0 mm-1.
Use the equations:
surface area of a cube = 6 × (side length)²
volume of a cube = (side length)³
surface area to volume ratio = surface area ÷ volume
Calculate the number of smaller cubes made from one cube of solid.
Explain how cutting the solid into smaller cubes affects the rate at which it reacts with the gas.
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.