Section 15 - Rates of Reaction and Energy Changes

Question 1

Rates of Reaction - What effect will raising the temperature have on the rate of a reaction?

Answer 1

The rate of reaction increases as the temperature increases

Question 2

Rates of Reaction - How does concentration affect the rate of reaction?

Answer 2

The higher the concentration of the reactants, the faster the rate of reaction will be

Question 3

Rates of Reaction - In a gaseous reaction, why would a decrease in pressure result in a lower rate of reaction?

Answer 3

If the pressure is increased, there will be more frequent collisions between the reactant particles and so this increases the rate of reaction. Therefore, lower pressure results in a lower rate of reaction

Question 4

Catalysts - What effect does a catalyst have on the activation energy needed for a reaction to take place?

Answer 4

A catalyst lowers the activation energy of a reaction, so that a chemical reaction can take place

Question 5

Catalysts - Give two examples of reactions catalysed by enzymes

Answer 5

1) Amylase — changes starches into sugars; found in saliva

2) Maltase — breaks the sugar, maltose into glucose; found in saliva

Question 6

Energy Changes in Chemical Reactions - What change in temperature would you expect to observe in an exothermic reaction?

Answer 6

The temperature increases

Question 7

Energy Changes in Chemical Reactions - What is activation energy?

Answer 7

Activation energy = the minimum amount of energy in order for a chemical reaction to occur

Question 8

Energy Changes in Chemical Reactions - Is energy required for the breaking of bonds or the forming of bonds?

Answer 8

The breaking of bonds