A student compares marble chips of different sizes but records only the time to collect 20 cm3 of gas. What is the dependent variable?
The size of the marble chips
The 20 cm320\,\mathrm{cm^3}20cm3 volume of gas collected each time
The time taken to collect 20 cm320\,\mathrm{cm^3}20cm3 of gas
The mass of marble chips used
54 exam-style questions on Edexcel GCSE Chemistry 8.1 Rates of reaction, covering 8.1.1 Measuring and interpreting rates of reaction, 8.1.2 Collision theory and the factors affecting rate, and 8.1.3 Catalysts and enzymes. Each one has a worked solution and a mark scheme showing where the marks go.