A 2.78 10-4 M solution of a compound has an absorbance of 0.425 at 520 nm in a 1.00 cm cell. The solvent's absorbance under the same conditions is 0.013.
What is the molar absorptivity of the unknown compound?
What is the concentration of the compound in a solution, if the absorbance of the solution in a 1.00 cm cell at 520 nm is 0.320?