229k views
1 vote
At 25 oC, 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 minutes at 25 oC? 3.12 x 10-2 M 47.4 M 2.11 x 10-2 M 4.67 x 10-2 M 8.72 M

User Iksemyonov
by
7.3k points

1 Answer

6 votes

Answer:


2.11\ * 10^(-2) is the correct answer to the given question.

Step-by-step explanation:

Given k=6.40 x 10-3 min-1.

According to the first order reaction .

The concentration of time can be written as


[\ A\ ]\ = \ [\ A_(0)\ ] * e \ ^\ {-kt}

Here
[\ A\ ]_(0) = Initial concentration.

So
[\ A\ ]_(0)= 0.0314 M

Putting this value into the above equation.


0.0314 \ *\ e^{6.40 x 10^(-3) \ * \ 62.0 }

=0.211 M

This can be written as


=\ 2.11 *\ 10^(-2)

User Goodolddays
by
6.4k points