Describe the two functions of a catalyst in terms of cause and effect.

1.) By bringing together react particles, catalysts places stress on the bonds of these particles
2.) This increases the rate of reaction because the reaction energy is released. 

Catalyst is the agent which alter the rat of chemical reactions.Catalyst is not consumed by the reaction as the other reactants. those catalyst which increases r speed up the reaction are known as positive catalyst.Those slows the reaction are known as negative catalyst.Catalyst may act by decreasing activation energy of reaction or by choosing an alternate pathway for the reaction.