Topic 1 - 1.2 - Factors affecting the rate of reaction

Question 1

Explain the collision theory

Answer 1

• For a reaction to occur, the particles that are reacting must collide with each other. ‘Successful’ collisions are certain collisions that cause a chemical change to happen.
• Greater number of ‘successful’ collisions = faster the rate of a reaction.

Question 2

Name the 4 factors that affect the rate of reaction

Answer 2

• Temperature
• Particle size
• Concentration
• Use of a Catalyst

Question 3

Explain how temperature affects the rate of reaction

Answer 3

Temperature increases = kinetic energy of reactant molecules increases

This causes collisions to occur more often with more energy, increasing the rate of reaction.

Question 4

Explain how concentration affects the rate of reaction

Answer 4

Concentration increases = more reactant particles moving together.

This causes collisions to occur more often, increasing the rate of reaction.

Question 5

Explain how particle size affects the rate of reaction

Answer 5

Reactant particle size decreased = surface area increased

Greater surface area = higher chance of collision and faster rate of reaction.

Smaller particle size = faster reaction rate.

Question 6

Explain how use of a catalyst affects the rate of reaction

Answer 6

Catalyst is present = reacting particles collide more successfully with less energy = reaction can take place at a lower temperature.

This increases the rate of reaction.

enzymes are catalysts and they remain unchanged during the reaction