Equal masses of iron wool react with oxygen under the same conditions. One sample of iron wool is tightly compacted before the reaction. Why does the compacted iron wool react more slowly?
The activation energy increases, so fewer collisions have enough energy to react
The oxygen particles have less kinetic energy, so fewer collisions are successful
Less iron surface is exposed to oxygen, so collisions occur less frequently
The oxygen pressure decreases, so oxygen particles collide with the iron less frequently
122 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.