Calculating the molar absorptivities


Assignment:

1) When measured in a 1.00 cm cuvet, a 9.45×10-4 M solution of species A exhibited absorbances of 0.155 and 0.687 at 450 nm and 725 nm, respectively. A 2.65×10-3 M solution of species B gave absorbances of 0.613 and 0.078 at 450 nm and 725 nm, respectively. Both species were dissolved in the same solvent, and the solvent's absorbance was 0.007 and 0.002 at 450 nm and 725 nm, respectively.

a) Calculate the molar absorptivities for species A.

b) Calculate the molar absorptivities for species B.

c) Calculate the concentrations of A and B in a solution that yielded the following absorbance data in a 1.00 cm cuvet: 0.496 at 450 nm and 0.875 at 725 nm.

2) Listed below are retention times and peak widths for an HPLC chromatographic separation on a 10 cm C12 column

     Compound          Time (min)          Width (min)       

        Unretained            0.954              
        Peak 1                   9.423                    0.1317
        Peak 2                   10.548                  0.1433
        Peak 3                   11.143                  0.1517
        Peak 4                   11.727                  0.1550
        Peak 5                   15.049                  0.1883

a) Calculate the theoretical number of plates for Peak 2.

b) Calculate the capacity factors for Peak 3 and Peak 4.

c) Calculate the relative retention between Peak 4 and Peak 5.

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Chemistry: Calculating the molar absorptivities
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