Question

A certain reaction has the form aA → bB. At a particular temperature and [A]0 = 2.80 × 10-3 molar, data was collected of concentration versus time for this reaction. A plot of 1/[A]t versus time resulted in a straight line with a slope value of 3.60 × 10-2 M-1s-1. What is the concentration of A after 300 seconds?
a.2.80 × 10-3 molar
b.2.72 × 10-3 molar
c.2.60 × 10-3 molar
d.3.60 × 10-2 molar

Answer 1

If the plot of 1/[A] versus time shows a constant slope, this means it is a second-order reaction. The equation would be:
1/[A] - 1/[A]0 = kt
1/[A] - 1/0.0028 = 0.036(300)
1/[A] = 0.00272 = 2.72 x 10^-3 M
This is equivalent to choice B.