# A certain reaction follows zero-order kinetics. Suppose the reaction went to 50% completion after 10 minutes. What percentage of completion does the reaction reach in an additional 5 minutes?

Aug 4, 2017

75%

#### Explanation:

"Zero order" kinetics means that the rate = k and is independent of the amount of material present. Thus, if the rate is such that the reaction is 50% complete in 10 minutes, in another 5 minutes another 25% of the overall reaction is complete - 75% of the total reaction.

The total reaction will be completed in 20 minutes.

Aug 4, 2017

75% complete.

A reaction following zero order kinetics has the rate law:

$r \left(t\right) = k {\left[A\right]}^{0} {\left[B\right]}^{0} \cdots$

and the rate is equal to the rate constant. Consequently, the rate of consumption of all the reactant(s) is a constant, and one could plot concentration $\left[A\right]$ of reactant $A$ vs. time $t$ to model the reaction progress.

This curve would then be a straight line:

And as such, it allows us to use the reaction progress as indicative of the fraction of $\left[A\right]$ leftover. 50% completion therefore means 50% of $\left[A\right]$ is gone.

Since that occurred in $10$ minutes, and the rate is constant, in $5$ minutes the reaction proceeds by half of 50%. As a result, the reaction is color(blue)(ul(75%)) complete after $5$ additional minutes, or $\left[A\right] = 0.25 {\left[A\right]}_{0}$.