- Created by: abbiedye
- Created on: 25-07-18 14:50
What is an Exothermic Reaction?
- A reaction that transfers energy to the surroundings usually by heating, indicated by a rise in temperature
- Examples are combustion, neutralisation reactions (acid + alkali) and oxidation reactions (sodium added to water)
Everyday examples are hand warmers and self-heating cans
1 of 4
What is an Endothermic Reaction?
- A reaction that takes in energy from the surroundings, indicated by a fall in temperature
- Examples are reactions between citric acid and sodium hydrocarbonate, thermal decomposition
- An everyday example is sports injury packs
2 of 4
How are bonds formed and broken?
- Energy must be supplied to break existing bonds in bond breaking (endothermic)
- Energy is released when new bonds are formed in bond forming (exothermic)
3 of 4
How do you calculate bond energies?
- Find the energy required to break the original bonds
- Find the energy released by forming the new bonds
- Find the overall energy change for the reaction using the equation:
- overall energy change = energy required to break bonds - energy released by forming bonds
4 of 4