Unit 5- Energy Changes

Question 1

What is an Exothermic reaction

Answer 1

One which transfers energy to the surroundings usually by heating. This is shown as a rise in temperature

Question 2

What is an endothermic reaction

Answer 2

Reactions which takes energy in from the surroundings, this is shown as a fall in temperature

Question 3

Example of Exothermic reaction

Answer 3

Neutralisation, combustion

Question 4

Uses of Exothermic reactions

Answer 4

Hand warmers- use the Exothermic oxidation of iron in air to release energy
Self heating cans

Question 5

Example of endothermic reaction

Answer 5

Thermal decomposition

Question 6

Uses of endothermic reactions

Answer 6

Used in sport injury packs, allows pack to become instantly cooler without having to be put in freezer

Question 7

What is a fuel cell

Answer 7

Electrical cell that produces electricity using fuel and oxygen

Question 8

Uses of fuel cells

Answer 8

Used in vehicles- don’t produce nasty pollutants, however uses a lot of energy

Question 9

What is equilibrium

Answer 9

Rate of forward and background reactions are equal in a closed system where nothing is added or taken away