For the reaction A + 2B ? 2C + D, the rate law is Rate = k[A]2. What is the overall order of the reaction? If k = 3.8 x 10-5 M s-1, how long will it take for the concentration of A to decrease from 1.0 M to 0.25 M? If [Bo] = 1.5 M, what will be the concentration once [A] = 0.25 M?