Name: All About Chemical Kinetics
Uploaded: 2019-07-19
Duration: 9 min 10 s
Description: Chemical kinetics is also called reaction kinetics. In this video, we will understand the rates of chemical reactions and the order of reactions.

Question

Models can prove vital in chemistry. Discuss the principles of the kinetic molecular theory and the collision theory.

Accepted Answer

According to the kinetic molecular theory of gases, a sample of gas is modelled as consisting of a collection of particles moving at high velocities in random directions, the sizes of the particles are negligible, the particles collide with each other, and with the walls of the container containing the gaseous sample. All the collisions are elastic. The pressure exerted by the gas results from collisions of its particles with the walls of the container. The average kinetic energy of the molecules increases with the increase in absolute temperature.

Collision theory: According to this theory,

(i) The reacting molecules are assumed to be hard, rigid spheres. The reaction takes place only when the reacting molecules collide.

(ii) The products are formed only if the colliding molecules have activation energy or more.

(iii) Frequency of collisions: If the total number of collisions per second in unit volume is $Z$ , the fraction of molecules possessing activation energy is $e^{- \frac{E_{a}}{RT}}$ , then the rate of the reaction is given by, rate $= Z e^{- \frac{E_{a}}{RT}}$ .

(iv) Orientation factor: All collisions between the activated molecules do not lead to the reaction. Products are formed if the colliding molecules are properly oriented to each other that the group reacting or bonds to be shifted are relatively close. Such collisions are called effective collisions.

Models can prove vital in chemistry. Discuss the principles of the kinetic molecular theory and the collision theory.

Important Questions on Chemical Kinetics

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