Question

Part A

The rate constant for a certain reaction is k = 3.70×10−3 s−1 . If the initial reactant concentration was 0.200 M, what will the concentration be after 11.0 minutes? Express your answer with the appropriate units.

Part B

A zero-order reaction has a constant rate of 2.00×10⁻⁴M/s. If after 65.0 seconds the concentration has dropped to 3.50×10⁻²M, what was the initial concentration?

Express your answer with the appropriate units.

Answer 1

For part A, Is this a first order reaction? if it is, then the equation to use is the following:

lnA = lnAo - kt

If it's a second order reaction the equation to use is:

1/A = 1/Ao + kt

And for part B) a zero order reaction is:

A = Ao + kt

But please be specific in part A). I will assume is a first order reaction, but if it's another order, just use the equation for that order and replace the values, it's easy:

A) for a first order reaction:

lnA = ln(0.2) - (3.7x10^-3) (11 min * 60 s/min)

lnA = -1.6094 - 2.442

A = 0.0174 M

B) A = Ao + kt

Ao = A - kt

Ao = 3.5x10^-2 - (2x10^-4)(65)

Ao = 0.022 M

Hope this helps