14-14 Spectroscopy 4

Converting %Transmittance to Absorbance and Absorbance to %Transmittance

1. The molar absorptivity of a substance at 650nm is 1.6 x 10⁵ cm^-1 M^-1. What is the concentration if the absorbance is 1.80 at 650nm of a sample in a 1cm wide cuvette?

2. What is the %Transmittance for the solution in question 1?

3. What is the absorbance and concentration if you take 20.0mL of the solution in question 1 and dilute to 200.0mL?

4. At 580nm, the molar absorptivity of a substance is 6.9 x 10⁴ cm^-1 M^-1 and the absorbance is 0.52. If the concentration is halved, what is the new %Transmittance?

5. At 580nm, the molar absorptivity of a substance is 6.1 x 10⁴ cm^-1 M^-1 and the absorbance reads infinity on a Spec20. You dilute the concentration by a factor of 1000, and the absorbance is 0.78 for the diluted solution. What is the concentration of the original solution?