1. Define “rate,” OR give an example of a rate
Mr. Quinn & Ms. Tom March 13, Aim: What influences the rate of a chemical reaction? Do Now:
Define “rate,” OR give an example of a rate

2. Introduction In order to react, molecules must: Collide
With enough energy
In the proper orientation

3. The effect of Temperature on Rate of Reaction
Let’s Try It Out!
The effect of Temperature on Rate of Reaction
As temperature increases, rate of reaction increases.
As temperature decreases, rate of reaction decreases.
Temperature affects the energy of the particles.
Temperature
Time to Dissolve
Cold
Room Temperature
Hot

4. The effect of Surface Area on Rate of Reaction
Let’s Try It Out!
The effect of Surface Area on Rate of Reaction
As surface area increases, rate of reaction increases.
As surface area decreases, rate of reaction decreases.
Surface area affects the number of collisions of the particles.
Surface Area
Time to Melt
Low (solid)
High (crushed)

5. The effect of Pressure on Rate of Reaction
Let’s Try It Out!
The effect of Pressure on Rate of Reaction
As pressure increases, rate of reaction increases.
As pressure decreases, rate of reaction decreases.
Pressure affects the number of collisions of the particles.
Pressure
Product Formed
Low
Medium
High

6. Your Turn!

7. Your Turn! What is required for a chemical reaction to occur?
standard temperature and pressure
a catalyst added to the reaction system
effective collisions between reactant particles
an equal number of moles of reactants and products

8. Your Turn!
As the temperature of a chemical reaction in the gas phase is increased, the rate of the reaction increases because
fewer particle collisions occur
more effective particle collisions occur
the required activation energy increases
the concentration of the reactants increases

9. Your Turn!
Why can an increase in temperature lead to more effective collisions between reactant particles and an increase in the rate of a chemical reaction?
The activation energy of the reaction increases.
The activation energy of the reaction decreases.
The number of molecules with sufficient energy to react increases.
The number of molecules with sufficient energy to react decreases.

10. Your Turn!
As the number of effective collisions between reacting particles increases, the rate of reaction
Decreases
Increases
remains the same

11. Your Turn!
At STP, which 4.0-gram zinc sample will react fastest with dilute hydrochloric acid?
Lump
Bar
Powdered
sheet metal

12. Your Turn! Given the reaction: Mg + 2 H2O → Mg(OH)2 + H2
At which temperature will the reaction occur at the greatest rate?
25°C
50°C
75°C
100°C

13. Your Turn!
Oxygen reacts with the surface of a solid zinc sample. Provide TWO methods for increasing the rate of this reaction.
Increase the temperature
Increase the surface area