Exothermic and Endothermic Reactions

Question 1

What is an exothermic reaction?

Answer 1

When energy is transferred from the reactants to the surroundings

So the temperature of the surroundings increases

Question 2

What is an endothermic reaction?

Answer 2

When energy is taken in from the surroundings

So the temperature of the surroundings decreases

Question 3

In an exothermic reaction, is the overall energy change negative or positive?

+ why?

Answer 3

Negative

This is because energy is transferred to the surroundings so the energy of the products will be less

Question 4

In an endothermic reaction, will the overall energy change be negative or positive?

+ why?

Answer 4

Positive

As energy is taken in from the surroundings so the energy of the products will be greater

Question 5

What is activation energy?

Answer 5

The minimum amount of energy required for a reaction to take place

Question 6

What is the law for the conservation of energy?

Answer 6

Energy cannot be created or destroyed only transferred from one store to another

Question 7

Give three examples of EXothermic reactions

Answer 7

Combustion

Oxidation

Neutralisation

Question 8

Give three examples of ENdothermic reactions?

Answer 8

Thermal decomposition (like ice melting)
Reaction of citric acid

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