Using the data below, plot a graph and answer the following questions. $($graph plot $10$ marks$)$

A $2\mathrm{.}845g$ sample of an unknown compound containing copper $($II$)$ ion was dissolved in water in a $250$

$mL$ volumetric flask. The absorbance of this solution was found to be $0\mathrm{.}2195$ at $515nm$ in a $0\mathrm{.}05m$ cell.

A$.$ Use the graph to find the concentration of copper $($II$)$ ion in the solution. $(5$ marks$)$

B$.$ Calculate the percentage of cobalt in the unknown compound. $(5$ marks$)$

C$.$ What percent of light is transmitted by the original copper $($II$)$ solution? $(5$ marks$)$

D$.$ What concentration of Copper II will absorb $50\%$ of the entering light? $(5$ marks$)$