Answer to Question #70443 in General Chemistry for aseel

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

(1) For the reactions involving two and more particles, the rate of reaction will depend on the chance of collision of those particles. The more particles are present in the volume unit, the more is the probability of the collision. As for the reactions involving only one particle, the collisions are irrelevant, and in this case the more molecules are present in a volume unit, the more molecules have enough energy for the
chemical reaction, increasing its rate.

(2) More frequent collisions of the particles upon heating explain the speed up of the rate of reaction. Although this seems straightforward, the rate of reaction also depends on the number of the molecules that have the energy superior to activation energy of the reaction, rending only this type of collisions productive and diminishing the effect of heating.

(3) A catalyst provides an alternative route for the reaction with lower activation energy. Thus, the number of molecules that pass the energy barrier increases, speeding up the reaction.