C5- Energy Changes

Question 1

Exothermic reaction

Answer 1

Transfer energy to the surroundings usually by heating eg. Burning fuels (combustion)

Question 2

Examples of exothermic in everyday life

Answer 2

Hand warmers, self hesting cans

Question 3

Endothermic reaction

Answer 3

Takes in energy from surroundings

Question 4

Examples of endothermic reaction

Answer 4

Reaction between citric acid and sodium hydrogencarbonate, thermal decomposition, sports injury packs

Question 5

Energy transfer RP

Answer 5

1. Taking temperature of reagents mixing them in polystyrene cup and measuring thr temperature of solutiin at end of reaction
2. You can reduce energy lost to surroundings by putting cup in beaker of cotton wool to give more insulation

Question 6

Reactions profiles (exothermic)

Answer 6

Exothermic reaction- products lower energy than reactants, initial rise (activation energy’
Products lowest point due to energy release

Question 7

Reaction (endothermic)

Answer 7

Products higher energy than reactants

Question 8

Bond energies

Answer 8

Energy must be supplied to break bonds- so bond breaking is an endothermic process
Energy is released when new bonds are formed- so bond formation is an exothermic process