Problem:

To see the difference between an atomic emission spectrum (helium light) and a complex molecular spectrum (chemiluminescence).

Introduction:

Chemiluminescence is a chemical reaction that produces light. This reaction does not have an excition source or heat source. The spectum of chemiluminescence is from energized molecules, not from excited atoms like from the helium source.

 My experiment will compare the spectra of a helium light source to the spectra of a chemiluminescence reaction. In this analysis, I will be using a mixture of 50 g of bis(2,4,6)-trichloro)oxalate, 3 g of 9-(2-phenylethenyl)anthracene, 0.2 mL of 30 % hydogen peroxide, and 5 mL of diethyl phthalate. These reagents combine to form light and 9,10-Diphenylanthracene, which is composed of mostly hydrogen and carbon. For my experiment, I will run both light sources through the spectrometer to see how the atomic structure affects the emission spectra.

Method:

I mixed the chemicals together and placed them in a vial. I then put the vial in front of the slit of the spectrometer. The spectrometer took 13 seperate intragration sections between the wavelengths 400 and 660 nm.

I repeated the experiment using a hydrogen light source. ELABORATE!!!

Data:

Graph of Chemiluminescent Spectrum

Graph of Chemiluminescent Spectrum

Discussion:

The graph had a peak at 490 nm This amount corresponds to the visable XCOLOR light spectrum. The peak was broad with wavelengths ranging from 425 - 650 nm, with a larger rising slope than decaying. The hydrogen spectra had one main, sharp peak at N nm. This amount corresponds to the visable XCOLOR light spectrum.

Conclusion:

The complexity of the glowing material caused the broad spectrum. Simple elements, like helium and sodium, produce sharp lines at known points.

Acknowledgements:
Mark Peterson
Jean Bennett
Janice Hudgings
Courtney Cushner
Katie Trandem

References:
http://www.chemistry.adelaide.edu.au/external/Soc-Rel/Content/mol-lvls.htm
http://www.shsu.edu/~chm_tgc/chemilumdir/chemiluminescence.html

Williamson, Kenneth. Macroscale and Microscale Organic Experiments. Houghton Mifflin Company. Boston. 1999. Pages 656-663