Chemical Kinetics

Question 1

Define Chemical Kinetics

Answer 1

It is a branch of science that deals with the rate of chemical reaction, factors affecting this rate, and the mechanism by which the mechanism takes place.

Question 2

Types of Chemical Reactions

Answer 2

1. Very fast reaction
2. Very slow reaction
3. Moderate reaction

Question 3

Define the Rate of Reaction

Answer 3

It is defined as the change in concentration of reactants or products per unit of time.

Question 4

Average the rate of reaction

Answer 4

It is defined as the change in concentration of reactants or products divided by the time interval at which change takes place.

Question 5

What is the instantaneous rate of reaction

Answer 5

The rate of reaction of a specific instant.

Question 6

What is the rate law

Answer 6

Rate law (R) is defined as the experimentally determined equation that expresses the rate of reaction in terms of the molar concentration of reactants.

Question 7

Applications of the rate of law

Answer 7

1. The rate law can be used to estimate the rate of reaction for any given composition of the reaction mixture
2. It can be used to estimate the concentration of reactants and products at any time during the course of reactions
3. It is useful to predict the mechanism of complex reactions

Question 8

What is the rate constant?

Answer 8

The rate constant (K) is defined as the rate of reaction when the molar concentration of reactants are set equals to unity

Question 9

Describe order

Answer 9

1. The sum of the powers of the concentration of reactants in the rate law expression is called the order of that reaction
2. It is a property of elementary as well as a complex reaction
3. It is experimentally determined value
4. It may be zero, fraction, or integer
5. Is dependent on experimental condition
6. It gives an idea about the rate of reaction
7. Classification:- 0, 1st, 2nd, 3rd, etc…

Question 10

Describe Molecularity

Answer 10

1. It is the number of reactant molecules taking part in the reaction
2. It is a property of only elementary and has no meaning for complex reaction
3. It is theoretically determined value
4. it can never be zero or fractional it will always be an integer
5. Independent of experimental condition
6. It does not give any idea about the rate of reaction
7. Classification:- unimolecular, bimolecular, trimolecular, etc

Question 11

Define Molecularity

Answer 11

It is defined as the number of reactant molecules taking part in the reaction

Question 12

Define Elementary reaction

Answer 12

The reaction which cannot be broken down into much simpler reaction

Question 13

Define Complex reaction

Answer 13

The reaction which takes place in two or more steps

Question 14

Define Reaction Intermediate

Answer 14

It is a species that is formed in the first step and gets consumed in the subsequent step

Question 15

Define Rate determining step

Answer 15

When a reaction is done in two or more steps one of the steps is slowest than all of the step the slowest step in the reaction

Question 16

Define Integrate Rate Law

Answer 16

The equation which is obtained by integrating the differential rate law and which gives the direct relationship between rate of reaction and time

Question 17

Define half-life period

Answer 17

The time needed by the reactant concentration to fall one half of its initial value

Question 18

Define Zero order reaction

Answer 18

The reaction which is independent on the molar concentration of reactants

Question 19

What is a pseudo-first-order reaction

Answer 19

The reaction which has higher order true rate law but is found to behave as a first-order reaction

Question 20

Requirement for Bimolecular reaction

Answer 20

1. Collision between two molecules
2. Activation of energy
3. Proper orientation of the molecule

Question 21

Define activation energy

Answer 21

For a reaction to occur the colliding reactant molecule must possess minimum kinetic energy, this minimum kinetic energy is called as the activation energy or threshold kinetic energy. (DOUBT)