Energy change

Question 1

Exothermic reactions

Answer 1

When energy is released to the surroundings
Causes the temperature of the surroundings to increase
Energy change is negative as energy is being lost

Question 2

Endothermic reactions

Answer 2

Energy is absorbed from the surroundings
Causes the temperature of the surroundings to decrease
Energy change is positive as energy is being absorbed

Question 3

Examples of Exothermic reactions

Answer 3

Combustion
Neutralization
Respiration

Question 4

Examples of Endothermic reactions

Answer 4

Thermal decomposition
Photosynthesis

Question 5

Bond making and breaking

Answer 5

Making bonds-Exothermic
Breaking bonds-Endothermic

Energy change is usually measured in KJ

Question 6

Where are exothermic reactions used

Answer 6

Hand warmers and self heating cans

Question 7

Where are endothermic reactions used

Answer 7

Sports injury packs

Question 8

Activation energy

Answer 8

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

Question 9

What happens in a chemical reaction

Answer 9

Energy must be supplied to break bonds in reactions and energy is released when new bonds are formed

Question 10

What happens in an Exothermic reaction

Answer 10

In an exothermic reaction the energy released when forming new bonds is greater than the energy released when breaking existing bonds

Question 11

What happens in an Endothermic reaction

Answer 11

In an endothermic reaction the energy released when breaking existing bonds is greater than the energy released when forming new bonds