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Homework Statement
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.
Homework Equations
Beers law E = A/bc
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.