Chem 2 Labs  WS96                      3/6/96  TB
Colorimetry & Spectrophotometry 
POSTLAB

1.  The wavelengths of maximum absorbance for the dyes used in this experiment 
occur at 520 and 620 nm.  Using information on the color vs wavelength for
the visible region of the electromagnetic spectrum, what color regions do these
wavelengths correspond to? 






 
This information may be obtained in the materials contained in the: 
MSDS/General Useful Info About Lab, link in the Chem 2 web page
in the link to Info on the Electromagnetic Spectrum
 
If your web browser doesn't display color images, you need to use a better browser.  
This information may also be found under electromagnetic radiation 
in the index of your freshman text.

2.  What hazards are presented by the dyes used in this experiment?






3.  What are the basic components (parts) of a spectrophotometer?








4.  A 0.974 ppm standard solution of a dye gives an absorbance of 0.763.  
A solution of the same dye of unknown concentration gives an absorbance of 0.534.  
What is the concentration of the dye in the unknown solution?