1. Chemical Reactions
2.4
10 September 2014

2. What is a chemical reaction?
A chemical reaction is a substance change resulting from breaking and reforming bonds.

3. What are reactants and products?
6O2 + C6H12O6 6H2O + 6CO2 (reactants) (products) Reactants are changed. Products are produced (made)

4. What is energy?
Energy is defined as the capacity to perform work (moving an object or particle).

5. What is bond energy?
Bond energy is the amount of energy that will break a bond between two atoms. Ex. H-O has bond energy 467 KJ/mol. C-O has bond energy 358 KJ/mol.

6. What is chemical equilibrium?
Equilibrium is when both reactants and products are made at the same time. CO2 + H2O H2CO3 Bidirectional: Two directions Same rate in both directions

7. What is activation energy?
Activation energy is the amount of energy that needs to be absorbed for a reaction to start.

8. What is activation energy?

9. Exothermic RX
Exothermic RXs releases more energy than they absorb. Products warmer & brighter than reactants.

10. Exothermic RX

11. Exothermic example: glucose
6O2 + C6H12O H2O + 6CO2 + +
C-O bond energy 358 KJ/mol
O-H bond energy 467 KJ/mol

12. Endothermic RX
Endothermic RX absorb more energy than they release. Products cooler than reactants.

13. Endothermic RX

14. Remember…