Chapter 4 Chemical kinematics Chemistry Class 12 Chapter 4 Chemical Kinematics Chemistry Class 12 | Page 8

( ii ) Initial rate method In this method , the order of a reaction is determined by varying the concentration of one of the
Reactants while others are kept constant .
( ii ) Integrated rate law method In this method out different integrated rate equation which gives the most constant value for the rate constant corresponds to a specific order of reaction .
( iii ) Half-life period ( t 1 / 2 ) method In general half-life period ( t 1 / 2 ) of a reaction of nth order is related to initial concentration of the reactant as
This method is employed only when the rate law involved only one concentration term .
( v ) Ostwald ’ s isolation method This method is employed in determining the order of complicated reactions by isolating one of the reactants so far as its influence on the reaction rate is concerned .
Temperature Dependence of Rate of a Reaction
For every 10 ° C rise in temperature , the rate of reaction becomes double , but only 16 % collisions increases . It can be explained by Arrhenius equation .
Temperature coefficient is the ratio of rate constant of a reaction at two temperature differing by 10 . Temperature selected are usually 298 K and 308 K
Temperature coefficient = Rt + 10 / Rt ≈ 2 to 3