1. The problem statement, all variables and given/known data Calculate the molar absorptivity of K2Cr2O7 at 455 nm given that 36.5 mg disolved in 500.0 mL exhibits 12.0% transmittance at 455 nm in a 2.000 cm cell. 2. Relevant equations Beers law E = A/bc 3. The attempt at a solution I was able to do the following part ( i solved for concentration of K2Cr2O7 ) I found the atomic mass of K2Cr2O7 [(0.0365 g)/(294.07 g/mol)] / (0.5000 L) = 2.482 x 10^-4 Now I plug this into beers law but the question asks for something about a 12.0% transmittance. I am stuck here. How does transmittance relate to molar absorptivity? I basically have 2 unknowns in one equation... what do I need to do next? E = A / [(2.000 cm)(2.482 x 10^-4)] and I need to solve for A.