12)
where, [R]1 and [R]2 are the concentrations of the reactants at time
t1 and t2 respectively Subtracting (3 12) from (3 11)
ln[R]1– ln[R]2 = – kt1 – (–kt2)
[
]
[ ]
(
)
−
=
1
2
1
2
lnR
R
t
t
k
(
)
[
]
[
]
1
2
1
2
1
R
ln
R
k
t
t
=
−
(3