The decomposition in water of an insecticide used for mosquito control follows first order kinetics irate constant of 1.45 years^{-1} at 10 degrees Celsius. Summertime spraying near a small Lake results in a lake concentration of 5.0 times 10^{-7} M for the insecticide.

a.) Assuming the average temperature of the lake is 10 degrees Celsius and no more insecticide enters the lake what would be the lake concentration of the insecticide after one year?

b.) How long will it take for the insecticide concentration in the lake to drop to 3.0 * 10^{-7} M?

c.) what is the half life, t_{1/2}, for the decomposition of the insecticide?

#### Top Answer

(a) For first order; lnAt = -kt + lnAo lnAt = - 1.45 x 1 + ln (5.0 x 10^-7) = -15.9587 At = e^(-15.9587) = 1.2 x 10^-7... View the full answer