Problem: Assume the human eye can detect light with transmittance of 0.35. The colored form of the indicator has ε = 8.79 x 10^5. and λmax = 580 nm. How much indicator in ml should be used if the indicator has concentration 0.1% w/w in water. Equation Used: Beer's Law = A = εbc where ε is given as 8.79 x 10^5 b = 1.00cm A= -logT = -log(0.35) = 0.456 Using Beer's Law, I solved for C and got 5.08(10^-7)mol/L But I don't know what to do to find the amount of indicator needed. The molecular formula is C15H6N4 if that helps.