C7 - Energy Changes

Question 1

What is an Exothermic Reaction?

Answer 1

A reaction where energy is given out TO the surroundings (temperature of surroundings INCREASES).

Question 2

What is an Endothermic Reaction?

Answer 2

A reaction where energy is taken IN from the surroundings (temperature of surroundings DECREASES).

Question 3

What is Activation Energy?

Answer 3

The MINIMUM amount of energy that particles need to react.

Question 4

Give an example of an Exothermic Reaction.

Answer 4

Combustion / Oxidation / Neutralisation

Question 5

Give an example of an Endothermic Reaction.

Answer 5

Thermal Decomposition / Photosynthesis

Question 6

What is the “Bond Energy” equation?

Answer 6

Energy of reaction = sum of bonds broken - sum of bonds made

Question 7

What is a chemical cell?

Answer 7

2 electrodes dipped in an electrolyte solution. It produces electricity from a chemical reaction.

Question 8

What is a battery?

Answer 8

2 or more cells connected in series.

Question 9

Describe the difference between rechargeable and non -rechargeable cells?

Answer 9

Rechargeable - chemical reactions can be reversed when an external current is supplied.

Non-rechargeable - reactants are used up so cannot be recharged.

Question 10

What is a fuel cell?

Answer 10

Fuel cells are supplied by fuel and oxygen to oxidise the fuel to generate electricity.