Rates of Reaction

Question 1

state the equation for the mean rate of reaction

Answer 1

quantity of reactant used or product formed / time taken

Question 2

explain the collision theory

Answer 2

chemical reactions can only occur when reacting particles collide with each other and with sufficient energy

Question 3

explain activation energy

Answer 3

the minimum amount of energy particles must have to react

Question 4

state the factors which affect the rate of reaction

Answer 4

• concentration of reactants in a solution
• pressure of reacting gases
• surface area of solid reactants
• the temperature
• presence of a catalyst

Question 5

explain how changing the concentration of reactants in a solution affects the rate of reaction

Answer 5

increasing the concentration increases the frequency of collisions, and so increases the rate of reaction

Question 6

explain how changing the pressure affects the rate of reaction

Answer 6

increasing the pressure increases the frequency of collisions, and so increases the rate of reaction

Question 7

explain how changing the surface area affects the rate of reaction

Answer 7

increasing the surface area of solid reactants increases the frequency of collisions, and so increases the rate of reaction

Question 8

explain how changing the temperature affects the rate of reaction

Answer 8

increasing the temp increases the frequency of collisions and makes the collisions more energetic, and so increases the rate of reaction

Question 9

describe how catalysts increase the rate of reaction

Answer 9

by providing a different pathway for the reaction that has a lower activation energy