# Beer’s Law Calculations

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Name: _________________________

1. If you double the wavenumber, you _____________ the energy.

1. If you double the wavelength, you ______________ the energy.

1. How do transmittance, absorbance, and molar absorptivity differ? Which one is proportional to concentration?

1. A compound with molecular mass 292.16 g/mol was dissolved in a 5.00 mL volumetric flask. A 1.00 mL aliquot was withdrawn, placed in a 10.00 mL volumetric flask, and diluted to the mark. The absorbance at 340 nm was 0.427 in a 1.000 cm cuvet. The molar absorptivity at 340 nm is ε340 = 6130 M-1*cm-1.
1. Calculate the concentration of the compound in the cuvet.
2. What was the concentration of the compound in the 5 mL flask?
3. How many mg of compound were used to make the 5 mL solution?

1. Using the molar absorptivity data below, find the [x] and the [y] in a solution whose absorbance is 0.233 at 272 nm and 0.200 at 327 nm in a 0.100 cm cell.

ε (M-1cm-1)

λ (nm)

X

Y

272

16,400

3,870

327

3,990

6,420