The decomposition of N2O5 is a first-order reaction. At 25 C, it takes 5.2 hours for the concentration to drop from 0.140 M to 7.0×10^-2 M.
How many hours does it take for the concentration to drop from 2.8×10^-2 M to 1.4×10^-2 M?
From 0.480 M to 1.5×10^-2M?