The rate law for the decomposition of dinitrogen tetroxide (N2O4) is -d[N2O4]/dt = k [N2O4]
It takes 6.20 hours for the concentration of 1.00 M N2O4 to decrease to 0.250 M. How much more time is required for 0.250 M N2O4 to decrease to a concentration of 0.125 M?