Question

Two trials of a reaction were run in a lab where absorbance data was collected over time.
In trial $2$, the absorbance values for the reaction for each unit of time were higher than they were for trial $1$.
Also, the rate of trial $2$ was higher than that of trial $1$.
Which of the following is most likely the case?

• A. The concentration of one or more reactants was increased in trial $2$.
• B. The concentration of the reactants in trial $1$ was higher than that in trial $2$.
• C. The concentration of reactants was decreased for trial $2$.
• D. Something interfered with the reaction.

Answer 1

Answer: (A)

The concentration of one or more reactants was increased in trial $2$.

Absorbance$=\epsilon \times concentration\times pathlength\dots \left[Beerlaw\right]$

$\therefore$ Absorbance $\propto$ concentration.

Also rate of reaction $\propto$ concentration of reactant

$\therefore$ It is possible that the concentration of one or more reactant was increased in trial $2$, giving higher values in trial $2$.