The rate of a chemical reaction increases under the conditions (1)to(3). Explain the reason.

Question

The rate of a chemical reaction increases under the conditions (1)to(3). Explain the reason. (1) Concentration of the reactants is high. (2)Temperature of the reaction system is high. (3)Catalysts are present.

Answer 1

For (1) and (2) the reason has to due with the increase in the number of collisions between reactant molecules.  As the concentration increases, the chance of collision increases because there are more molecules/unit volume of solution. As the temperature increases, the kinetic energy of the reactant molecules increases, again increasing the likelihood of collisions. For (3) the catalyst provides an alternate pathway for the reaction to occur, and this alternate pathway has a lower energy of activation than the pathway in the absence of the catalyst. With a lower E_act, the reaction proceeds more rapidly.