Question

At 25 °C the rate constant for the first-order decomposition of a pesticide solution is 6.40 x 10-3 min-1. If the starting concentration of pesticide is 0.0314 M, what concentration will remain after 62.0 min?

Answer 1

Answer:

0.0211 M concentration of pesticide will remain after 62.0 min.

Explanation:

Initial concentration of the pesticide = $[A_o]=0.0314 M$

Final concentration of the pesticide after t time = $[A]=?$

t = 62.0 minutes

Rate constant of the reaction = k = $6.40\times 10^{-3} min^{-1}$

For the first order kinetics:

$[A]=[A]_o\times e^{-kt}$

$[A]=0.0314 M\times e^{-6.40\times 10^{-3} min^{-1}\times 62.0 min}$

$[A]=0.0211 M$

0.0211 M concentration of pesticide will remain after 62.0 min.