eguruchela

Chemical kinetics


Integrated rate law equation for zero order reaction

$$ \text {(a) k } = \frac{[R]_{\,o}–[R] }{t} $$ $$ \text {Where :} $$ $$ \text {k is rate constant , } $$ $$ [R]_{\,o} \text { is initial molar concentration and} $$ $$ \text {[R] is final concentration at time t.} $$ $$ \text {(b) } t_{\, \frac{1}{2}} = \frac{[R]_{\,o}}{2k} $$ $$ t_{\, \frac{1}{2}} \text { is half life period of zero order reaction.} $$

Integrated rate law equation for first order reaction

$$ \text {(a) k } = \frac{2.303}{t} \log \frac{[R]_{\,o} }{[R]} $$ $$ \text {Where:} $$ $$ \text {k is rate constant and} $$ $$ [R]_{\,o} \text { is initial molar concentration and} $$ $$ \text {[R] is final concentration at time t.} $$ $$ \text {(b) } t_{\, \frac{1}{2}} = \frac{0.693}{k} $$ $$ t_{\, \frac{1}{2}} \text { is half life period of first order reaction.} $$

Arrhenius equation

$$ \text {(a) k } = Ae ^{-Ea/RT} $$ $$ \text {Where:} $$ $$ \text {A is frequency factor, } $$ $$ \text {Ea is the energy of activation,} $$ $$ \text {R is universal gas contant and } $$ $$ \text {T is absolute temperature.} $$ $$ {-Ea/RT} \text { gives the fraction of collisions having energy = or> Ea.} $$ $$ \text {(b) } \log \frac{k _{\,2}}{k _{\,1}} = \frac{E _{\,a}}{2.303 R} ( \frac{T_{\,2} - T_{\,1}}{T_{\,1} T_{\,2}}) $$ $$ \text {Where:} $$ $$ k _{\,1} \text { is rate constant at temperature } T_{1}, $$ $$ k _{\,2} \text { is rate constant at temperature } T_{2}, $$