A stock solution is made by dissolving $7\mathrm{.}00g$ of cobalt$($II$)$ nitrate hexahydrate into enough water to

make $500\mathrm{.}0mL.$ This stock solution was diluted further to make a set of standard solutions, each

with a volume of $25\mathrm{.}00mL.$ The samples and absorbances measured for each solution

pathlength$)$ are given below.

Use the information provided along with Excel to create a calibration curve to determine the

absorptivity constant for $Co(N{O}_3{)}_2(aq),,$ and calculate the the concentration of a solution of

$Co(N{O}_3{)}_2(aq)$ with absorbance $0\mathrm{.}137.$ Calculate the following

Concentration of unknown

$mM$

$$

$M^{-1}c{m}^{-1}$