1. ENERGY & CHEMICAL CHANGE
REVISION

2. ENTHALPY Energy changes in reactions related to bond energy changes
HEAT OF REACTION (ΔH) as the energy absorbed or released in a chemical reaction.

3. ENERGY DIAGRAMS
EXOTHERMIC REACTIONS are reactions that release energy.
ENDOTHERMIC REACTIONS are reactions that absorb energy

4. ENDOTHERMIC REACTIONS

5. EXOTHERMIC REACTIONS

6. PROPERTIES
Activation energy is the minimum energy needed for a reaction to occur.
When bonds break energy is
absorbed
When bonds form energy is released

7. PROPERTIES
activated complex is the temporary unstablecompound formed when activation energy is reached

8. Potential energy of the reactants and products
PROPERTIES
Potential energy of the reactants and products

9. PROPERTIES
Change in enthalpy H

10. INFLUENCE OF A CATALYST

11. REVISION
RATE OF REACTION

12. REACTION RATE
reaction rate is the change in concentration of reactants or products per unit time.

13. Time
Mass of beaker

15. COLLISION THEORY
Chemical reactions occur when reactant particles collide to form product particles
Molecules need to collide with the correct orientation
Molecules need to collide with enough energy

16. MAXWELL-BOLTZMANN DISTRIBUTION CURVE
Reaction rate is directly proportional to the
Number of collisions per time
Portion with sufficient kinetic energy
Portion that collide with the correct orientation

17. FACTORS THAT AFFECT THE RATE OF CHEMICAL REACTIONS
nature of reacting substances
Concentration
Pressure
surface area
Temperature
 catalyst

18. NATURE OF REACTING SUBSTANCES
1st ionisation energy

19. CONCENTRATION & PRESSURE
Higher concentration means more particles,
more particles means more collisions,
more collisions mean more molecules with EA

20. TEMPERATURE High temperature means the particles move faster
it means more collisions between molecules withEA

21. CATALYST
A catalyst increases the rate of reaction by providing an alternative route with a lower activation energy.
It reduces the net / total activation energy
positive catalyst is a substance that increases the rate of a chemical reaction without itself undergoing a permanent change

22. Chemical reactions occur when reactant particles collide to form product particles
Molecules need to collide with the right orientation
Molecules need to collide with enough energy
Reaction rate is directly proportional to the
Number of collisions per time
Portion with sufficient kinetic energy
Portion that collide with the correct orientation
CONCENTRATION

23. CONCENTRATION

24. Chemical reactions occur when reactant particles collide to form product particles
Molecules need to collide with the right orientation
Molecules need to collide with enough energy
Reaction rate is directly proportional to the
Number of collisions per time
Portion with sufficient kinetic energy
Portion that collide with the correct orientation
TEMPERATURE

25. TEMPERATURE

26. Chemical reactions occur when reactant particles collide to form product particles
Molecules need to collide with the right orientation
Molecules need to collide with enough energy
Reaction rate is directly proportional to the
Number of collisions per time
Portion with sufficient kinetic energy
Portion that collide with the correct orientation
SURFACE AREA

27. SURFACE AREA

28. Chemical reactions occur when reactant particles collide to form product particles
Molecules need to collide with the right orientation
Molecules need to collide with enough energy
Reaction rate is directly proportional to the
Number of collisions per time
Portion with sufficient kinetic energy
Portion that collide with the correct orientation
CATALYST

29. CATALYST