# Chemical kinetics class 12 chapter full notes 2021

Chemical kinetics class 12 chapter full notes 2021 Chemical Force Dynamics | Chemical dynamics | Chemical kinetics

## Chemical Force Dynamics chemical dynamics Chemical Force Dynamics Chapter Full Notes Chemical Force Dynamics Chapter Full Notes | Chemical kinetics 12th

Chemical Force Dynamics | Chemical dynamics | Chemical kinetics

Chemical kinetics class 12 notes pdf chemical kinetics class 12 solutions chemical kinetics class 12 ppt chemical kinetics class 12 for neet chemical kinetics class 12 physics wallah

Chemical kinetics class 12 notes chemical kinetics class 12 pdf chemical kinetics class 12 ncert pdf chemical kinetics class 12 important questions chemical kinetics class 12 notes pdf

Chemical Force Dynamics :- The branch of chemistry under which the factors affecting the rate and velocity of reactions are studied is called chemical kinetics.

Reaction rate :- The change in the concentration of the reactants or products of a chemical reaction in a given time is called the rate of reaction.

Reaction velocity = ±(concentration of reactants or products)/(time taken to change)

Velocity of reactants = – time taken to change the concentration/change of reactants

Graph between concentration and time

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Average Velocity :- The rate of a reaction in a given time interval is called the average velocity, the average velocity is determined as follows

Average velocity for the reactants = ( – final concentration – initial concentration) / time

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Average velocity for the products = (+final concentration – initial concentration)/time

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Instantaneous velocity : The rate of reaction at any instant is called instantaneous velocity.

Instantaneous velocity for reactants = ± time taken for small change/change in concentration of reactants or products
instantaneous velocity for products

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Relation between rate of reaction and striometrics

Determination of rate of whole reaction To study the change in concentration of one reactant and one product with time, it is necessary that the equation of the reaction is balanced

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Law of Mass Proportional Reaction

The rate of a chemical reaction is directly proportional to the concentration of the reactants participating in it, this is called the law of mass ratio reaction.

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In the above equation, the rate expression or rate equation or rate law of a chemical reaction is called

Method of writing rate expression :- The rate expression of a chemical reaction cannot be written only with balanced equation, but to write it, it is necessary to know the kinetics of the reaction, the kinetic of the reaction tells that by changing the concentration of a reactant. how does the rate of a reaction change
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Velocity Constant/Velocity Expression/Velocity Law :-

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Note – If the concentration of the reactants of a reaction is unit, then the rate of this reaction is called specific reaction rate.

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Molecularity of the Reaction

(1) The sum of the number of reactant molecules present in a balanced equation of a chemical reaction is called the molecularity of the reaction.

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(2) A theoretical amount of the molecular of the reaction is

(3) Molecularity of a reaction can never be zero or fractional

(4) The molecularity of the reaction cannot be 4 or more because it is not possible for 4 reactant molecules to collide together at ‘one place’

(5)- The mechanism of reaction cannot be determined by the molecularity of the reaction.

Order of Reaction

(1)- The sum of the exponents of the concentration terms present in the experimental value rate expression of a reaction is called the order of the reaction.
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(2)- The order of the reaction is an experimental quantity.

(3)- The value of the order of reaction can be zero or even fractional.

(4) The order of the reaction may also be the same molecular number, but it is not necessary that the number of molecules of a reaction should be the same order.

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(a) – The reaction of H2 and Cl2 is made on the surface of water in the presence of light, then its order is zero while its molecularity is 2.
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(b) Acidic hydrolysis of an ester is a first order reaction when its molecularity is 2.
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Factors affecting the rate of reaction

(1)- Concentration of Reaction : – We know that initially the concentration of reactants is maximum, so the rate of change in concentration is also high, as the concentration of reactants starts decreasing, the rate of reaction also decreases i.e. reaction The velocity of the reactants is proportional to the concentration of

(2)- Temperature of the system : – The rate of almost all the reaction increases with increase in normal temperature, this is because the kinetic energy of the reactants increases with the increase of temperature and according to the collision principle (condensation theory), there are mutual collisions in molecules O. The number of molecules also increases, as a result the rate of conversion of reactant molecules into products increases, that is, the rate of reaction increases.

(3)- Nature of reactants and products :- The rate of reaction is also affected by the nature of reactants and products.
For example, the oxidation of nitric oxide to nitrogen dioxide is rapid, whereas the conversion of carbon monoxide to carbon dioxide is slow, i.e. the reactivity of substances depends on the easy breakdown of specific bonds.
2No+O2——> 2No2(Sharp)
2Co+O2——>2Co2(slow)

(4)- Effect of Catalyst :- Catalysts are those substances which increase the rate of reaction without any change in any chemical reaction.

As hydrolysis of ester is a slow chemical reaction but takes place rapidly in the presence of dilute acid.

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(5)- Surface Area :- The greater the surface area of ​​the reactant, the greater will be the rate of reaction, the more the substance is divided into smaller particles, the greater the rate of its reaction.
For example, when a wood is cut into small pieces, it burns directly, that is, the rate of reaction increases with increasing surface area.

(6) Effect of radiation :- Some reactions increase their velocity unexpectedly in the presence of radiation.
For example, the reaction of H2 and Cl2 takes place very slowly in the dark, but in the presence of ultraviolet light of the Sun, an explosive reaction takes place.
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Calculation of the integrated rate constant for a zero order reaction and

The reaction whose rate of reaction does not depend on the concentration of the reactants i.e. depends on the 0 watt of the concentration of the reactants is called zero order reaction.
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Half life time for zero order reaction – Half life time is the time at which half of the reactant is converted into product
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First order reaction and its integrated expression for it

The reaction whose reaction rate depends on the first moiety of the concentration of the reactants is called first order reaction.
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Half life period for first order reaction :- Half life period is the time at which half of the reactants are converted into products
t = t1/2
n = q/2
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Graphical representation for a reaction of the first order – If the graph is drawn between Log10 (a/(a-x) and time (t), then it is a straight line whose slope is

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Dependence of reaction rate on temperature – The rate of reaction is greatly affected by temperature. On increasing normal temperature, the rate of almost all reactions can be increased, on the contrary, the rate of reaction also decreases with decrease in temperature.

A general study According to this, the rate of a chemical reaction increases by 2 to 3 times on increasing the temperature of 10 °C, it is called the temperature coefficient.

Temperature coefficient – velocity constant at (T + 10)°c/velocity constant at T°c

Velocity theory of reactions

Collision Principle : –

For a reaction to occur in substances, it is necessary that there should be a collision between their molecules, as a result of the collision, the already existing bonds in the molecules are broken and a new type of rearrangement is obtained, as a result of which new bonds are formed

Collision theory is based on the principle that when the molecules of reactants A and B both come closer and collide with each other, it means that the speed of the reactions depends on the number of collisions i.e. the speed of the reaction is the number of collisions. is proportional to the number

=> There are three main points of collision theory
(1)- collision between reactant molecules
(2)- Orientation (direction) at the time of collision
(3)- activation of molecules

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 Chemical kinetics class 12 notes pdf chemical kinetics class 12 solutions chemical kinetics class 12 ppt chemical kinetics class 12 for neet chemical kinetics class 12 physics wallah

Activation Energy – Effective collision occurs only when the reactant molecules collide in the right direction. For the collisions to be effective a minimum amount of energy must be generated from the reactant molecules which convert the reactants into products is called activation energy. Meaning that the amount of energy obtained by the collision of reactant molecules which makes the reaction complete or as a result of which products are formed is called activation energy.

A + B-C ——-> A•••B•••C ——> (A—B)+C(Product)
Let the above reaction take place in one step, minimum energy is required to close A with B. A strikes BC on the side of B. A starts bonding with B and BC starts breaking. In this way, partial bonds are formed between A and B and B and C, this state is called transition state, this state is temporary, after which AB bonds are completely formed and BC bonds are completely broken.

Endothermic and exothermic reactions

The reaction in which the enthalpy of the products is more than the enthalpy of the reacting agents, in the completion of such reaction O, heat is absorbed from the periphery, hence they are called exothermic reactions,

On the contrary, the reaction in which the enthalpy of the products of action is less than the enthalpy of the action factors, the heat is released due to the completion of love, such a reaction is called exothermic reaction.

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Theory of Ahrenaeus

The main points of the Arrhenius theory are as follows

(1)- All the molecules present in a chemical reaction do not take part in the reaction, only those which have sufficient energy, these molecules are called active molecules.

(2)- Activated molecules have some more energy than other normal molecules of reactants, that minimum additional energy which is required for the reaction of the reactant molecules is called activation energy.

(3)- activation energy is obtained by collision of activation molecules

(4)- With increasing temperature, there is a significant increase in the ratio of the active molecule O

(5)- An equilibrium is established between the normal molecules of the reactant and the active molecule O.

(6)- When active molecules collide with each other, active hybrid is formed which is a high energy species.

These are actively converted into hybrid products
On the basis of the above points, Ahrenius explained a relationship between the rate constant and the absolute temperature (T), according to which the rate of reaction increases exponentially with increase in temperature.

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