k E R T T TT = T = 400K ; k = . s T = 200K ; k = . s log . s .
s E x . JK mol 400K = K 200K x K log ( ) = E x . JK mol K E x x . JK mol x K ( ) log E J mol Example Rate constant k of a reaction varies with temperature T according to the following Arrhenius equation log k log A E .303R T Where E a is the activation energy.
When a graph is plotted for log k V s T a straight line with a slope of -4000K is obtained. Calculate the activation energy Solution log log k A- E .303R T y = c + mx m = - E .303R E . R a = − m E . x .
J K mol x = − K E J mol a = , E kJ mol a = Evaluate yourself For a first order reaction the rate constant at 500K is X − s . Calculate the frequency factor, if the energy of activation for the reaction is kJ mol - . XII U7 kinetics - Jerald XII U7 kinetics - Jerald - - - -