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QURATULAIN MUGHALBATCH IV

DOCTOR OF PHYSICAL THERAPYISRA UNIVERSITY

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CHEMICAL KINEMATICS

DEFINITION:

“the branch of physical chemistry which deals with the rate of chemical reactions and the mechanism through which they occur is called chemical kinematics”

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RATE OF REACTION

• DEFINITION:

“the decrease in concentration of reactant or increase in concentration of the products of the reaction at a given moment of time is called rate of reaction”

FORMULA:

dx/dt=K

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CONTI…..

• Where,

dx=change in concentration

dt=time taken for change

K= reaction rate constant

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ORDER OF REACTION

• DEFINITION:“the number of reacting molecules whose

concentration alters as a result of chemical change is called the order of reaction”

OR“the sum of exponents in the rate expression of a

reaction is the order of reaction” OR“the power to which concentration of reactant is to

be raised to get the rate of reaction”

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CONTIN……

• EXAMPLES:

mA+rB product

rate = K[A] ͫ [B] ͫ

The oder of reaction= (m+r)

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TYPES OF ORDER REACTION

1. First order reaction

2.Second order reaction

3.zero order reaction

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FIRST ORDER REACTION

• If a reaction rate depends on a single reactant and the value of the exponent is one, then the reaction is said to be first order.

• r = k [A]

• FORMULA:

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FIRST ORDER REACTION

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SECOND-ORDER REACTION

• the rate of reaction is directly proportional to the square of the concentration of one of the reactants.

• r = k [A]2

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ZERO-ORDER REACTION

• For a zero-order reaction, the rate of reaction is a constant. When the limiting reactant is completely consumed, the reaction abrupt stops.

• r = k

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