Beer’s Law Calculations

Name: _________________________

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

 

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

 

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

 

 

 

 

 

 

 

 

4. 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 A 1.00 mL aliquot was withdrawn, placed in a 10.00 mL volumetric flask, and diluted to the mark.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?

       

       

       

       

       

      
      
      
      
      
      
       

5. 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

    

   
   
   
   
   
    

 

Contributors and Attributions

• Sarah Gray, Stockton University ([e-mail])
• Sourced from the Analytical Sciences Digital Library