# Wavelength and Absorbace

1. What is the wavelength of an emission line for iron that has a frequency of 5.68×1014 Hz?

2. A solution of CoL3+ has a percent transmittance of 28.9 % at 565 nm in a 2.00 cm cell. The molar absorptivity for the complex at this wavelength is 2.45×104 L/(mol?cm). What is the absorbance of CoL3+ in this solution?

3. A 2.50 mL aliquot of a solution that contains 3.8 ppm iron (III) is treated with an appropriate excess of KSCN and diluted to 50.0 mL. What is the absorbance of the resulting solution at 580 nm in a 2.50 cm cell? The complex FeSCN2+ has a molar absorptivity of 7.00×103 L cm-1mol-1. (Fe - 55.845 g/mol)

© SolutionLibrary Inc. solutionlibary.com 9836dcf9d7 https://solutionlibrary.com/chemistry/physical-chemistry/wavelength-and-absorbace-7dv1

#### Solution Preview

...l. The molar absorptivity for the complex at this wavelength is 2.45×104 L/(mol•cm). What is the absorbance of CoL3+ in this solution?
Most of the data in this problem is unnecessary. All you need to know is:

A is absorbance and is transmittance (in a decimal).
You can plug the knowns into the equation to solve:

3. A 2.50 mL aliquot of a solution that ...