Reaction Rates 1

The rate of a reaction can be determined by the :
1) rate at which reactants are used up
2) rate at which products are formed

The reaction rate can be expressed in the units : mol.s-1

Five Factors can affect the rate of a reaction between two substances:
1) Concentration (solutions)
2) Pressure (gases)
3) Temperature
4) Catalyst
5) Surface Area – extent of division into smaller pieces (solids)

An increase in concentration, pressure, temperature, or surface area will increase the rate of a reaction.

Increased Concentration
:: more reacting particles are present
> more collisions
> more effective collisions
> higher rate

Increased Pressure
:: the same number of particles are forced closer to each other
> more collisions
> more effective collisions
> higher rate

Increased Temperature
:: the same number of particles are made to move faster; higher kinetic energy
> more collisions
> more effective collisions
> higher rate

Add Catalyst
:: decrease in activation energy
> more collisions
> more effective collisions
> higher rate

Increase Surface Area
:: increase in exposed reacting surface
> higher reaction rate


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