1. Exothermic & Endothermic

2. The temperature of the surroundings increases
Exothermic reactions
An exothermic reaction is one which releases heat energy to the surroundings
The temperature of the surroundings increases
The energy released from forming new bonds is greater than the energy needed to break old bonds
Exothermic reactions

3. Exothermic reactions
Exothermic reactions

4. Exothermic reactions
Exothermic reactions

5. Endothermic reactions
An endothermic reaction is on which takes in heat energy from the surroundings
The temperature of the surroundings decreases
The energy needed to break old bonds is greater than the energy released from forming new bonds
Endothermic reactions

6. Endothermic reactions

7. Endothermic reactions

8. Reversible reactions
In a reversible reaction, if one reaction is exothermic, the reverse reaction must be endothermic
Reversible reactions

9. Reversible reactions
Reversible reactions

14. Exothermic reactions
Exothermic reactions

16. Summary If more energy is used breaking bonds than making bonds, then…
If more energy is used making bonds than breaking bonds, then…

17. Summary
If more energy is used breaking bonds than making bonds, then the reaction is (exo/endo)thermic.
Energy is (taken in/ given off) and the temperature of the surroundings (increases/decreases).
Draw the thermometer.
If more energy is used making bonds than breaking bonds, then the reaction is (exo/endo)thermic.

18. Problems CH4 + O2  CO2 + H2O H2O  H2 + O2 N2 + H2  NH3

19. Exothermic & Endothermic