Collision Theory

Factors affecting rate

Investigate how temperature affects rate

Collision Theory

1. For a reaction to occur the particles must collide

2. The colliding particles must have a minimum energy called the

Activation Energy

Factors affecting Rate of reaction

1. Concentration

2. Temperature

3. Particle size

4. Nature of reactants

5. Presence of a catalyst

Temperature, Collisions & Activation Energy

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Effect of temperature on rate

Increasing temperature increases the rate

By increasing the number of collisions / sec

More of the colliding particles have E Act

The formation of a pale yellow precipitate of sulphur can be used to monitor the progress of

the reaction

HCl Na2S2O3 H2O+NaCl

Investigate the effect of temperature on reaction rate

+ + S+ SO2

To investigate the effect of temperature on reaction rate

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Add the HCl to the Na2S2O3 in the flask

Record the time taken for the X to disappear

Record the temperature after mixing

Inverse the time to get the rate

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Repeat at different temperatures

Effect of temperature on rate

RATE

TEMPERATURE

Conclusion ?

Rate increases with increasing temperature

1

Time

Effect of temperature on rate

RATE

TEMPERATURE

What is the main factor

increasing rate between A and B

Rate increases due to increased collisions /sec

1

Time

A

B

Effect of temperature on rate

RATE

TEMPERATURE

What other factor caused the large rate

increase between B and C

More colliding particles have E Act

1

Time

C

B