Here's how to think about it.
Since a plot of
Therefore, you use the equations for a second-order reaction.
The integrated rate law for a second order reaction is
#color(blue)(bar(ul(|color(white)(a/a) 1/"A"_t = kt + 1/"A"_0color(white)(a/a)|)))" "#
The slope of the plot of
For a second order reaction,
#color(blue)(bar(ul(|color(white)(a/a) t_½ = 1/(k"A"_0) color(white)(a/a)|)))" "#
Since you now know the values of
Insert these values into the integrated rate law and solve for