Question one: Topic Molecular Spectroscopy (16 marks) * unknown = museture - contains salts You were given an unknown mixture that contains two metal salts (A) Co(NO3)2 and (B) Cr(NO3)2 and requested to determine their concentration. The following representative information about the absorbance data were also provided. Measurements were made in a 1.0 cm quartz cells. Pure A (mol/l) 1.5 x 10-1 0 Pure B (mol/l) 0 6 x 102 Abs @510 nm Abs @575 nm 0.714 0.097 0.298 0.757 0.330 Unknown conc in mixture Unknown conc in mixture 0.671 How would you go about calculating the concentration of the two salts?

Question one: Topic Molecular Spectroscopy (16 marks) * unknown = museture - contains salts You were given an unknown mixture that contains two metal salts (A) Co(NO3)2 and (B) Cr(NO3)2 and requested to determine their concentration. The following representative information about the absorbance data were also provided. Measurements were made in a 1.0 cm quartz cells. Pure A (mol/l) 1.5 x 10-1 0 Pure B (mol/l) 0 6 x 102 Abs @510 nm Abs @575 nm 0.714 0.097 0.298 0.757 0.330 Unknown conc in mixture Unknown conc in mixture 0.671 How would you go about calculating the concentration of the two salts?

Principles of Instrumental Analysis

7th Edition

ISBN:9781305577213

Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Publisher:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Chapter13: An Introduction To Ultraviolet-visible Molecular Absorption Spectrometry

Section: Chapter Questions

Problem 13.25QAP

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.Q1. To determine the concentrations (mol/L) of Co(NO3)2 (A) and Cr(NO3)3(B) in an unknown sample, the following representative absorbance data wereobtained.A (mol/L) B (mol/L) 510nm 575nm5×10−1 0 0.714 0.0970 6×10−2 0.298 0.757Unknown Unknown 0.671 0.330Measurements were made in 1.0 cm glass cells.i. Calculate the four molar absorptivities: ∈A(510), ∈A(575), ∈B(510) and ∈B(575).ii. Calculate the molarities of the two salts A and B in the unknown.
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An ethanol solution of 3.5 mg/100 ml of compound Y (150.0 g/mol) in a 1.00 cm quartz cell has an absorbance (A) of 0.972 at λmax=235 nm. What is its molar extinction coefficient? Report your answer to the correct number of significant figures. Do not include units in your answer.