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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