When the temperature of a substance is decreased, the rate of a chemical reaction will decrease, because the higher temperature will cause the particles to move faster and to increase the number and...
The higher temperature will cause the particles to move faster and to increase the number and strength of the collisions. So, a lower temperature will slow the speed at which the particles move and...
if the reaction is exothermic (creates heat) then adding heat will cause the reaction to run in the reverse direction
if the reaction is endothermic (requires heat) then heat will speed it up