Q1. A compound was characterized using UV-visible absorptionspectroscopy. The absorbance spectrum of a 1.00 x 10–4 mol/Lsolution in a 1.00 cm path length cell peaked at the wavelength of345 nm to a value of 1.32.

(1) What was used as a reference? Specify the cell and itscontents.

(2) What is the transmittance at that wavelength?

(3) What is the molar absorptivity at that wavelength?

Q2. Answer the following questions regarding quantitativeanalysis using UV-visible spectroscopy. Assume that thespectrometer gives you the raw intensity spectrum of thetransmitted light as a function of the wavelength only, and thelight source is stable.

(1) You are given a water-soluble compound. Explain how you canobtain the spectrum of specific absorption coefficient ε(λ) =Abs/(bc), where Abs is the absorbance spectrum, b is the pathlength, c is the mass concentration (wt% or g/mL).

(2) Let us assume that you have obtained specific absorptioncoefficient εa(λ) and εb(λ) for two water-soluble compounds a and bhaving different colors. You are given a mixture that consists ofthe two compounds and a third transparent compound. How can youfind the concentrations of and b (ca and cb, respectively) when thetotal concentration of the mixture in water is c (c > ca + cb).Explain the procedure.