Spectroscopy and Unknowns
Sarah Madden, Matt Grandbois, Eric Nelson
October 31 and November 7 2000
Chem 120 H / Viste
Introduction
The purpose of this lab was to identify an unknown using various methods of spectroscopy. The unknown could have contained any or all of these elements: carbon, oxygen, and chlorine. The number of carbon atoms in the unknown molecule ranged from one to six. The following methods of spectroscopy are various ways to obtain the spectrum of an unknown: FTIR (infrared), which relates to molecular vibrations; Raman, which relates to molecular vibrations; NMR (nuclear magnetic resonance); GC/MS (mass spectroscopy); and UV-vis (ultraviolet-visible). Other chemical characteristics that can help identify organic unknowns are the boiling point, refractive index, and the flame test.
Methodology:
The lab began with obtaining an unknown organic compound. The first test that was completed was the Beilstein’s flame test for the presence of chlorine. The next part of the labs involved observing different types of spectra through use of FTIR, Raman, NMR, GC/MS, and UV-vis. The refractive index and the boiling point of the unknown were also found. The results of these various tests along with the different spectra types were then analyzed and the unknown was identified.
Results:
Beilstein’s Test: no chlorine
Boiling Point: 139-141 o C
Refractive Index: 1.4504
FTIR (infrared):
Raman Spectra:
NMR (nuclear magnetic resonance):
GC/MS (mass spectroscopy):
UV-Vis (Ultraviolet-visible):
HOMO:
LUMO:
Cyclohexanone vibration 27:
Vibration Spectrum 35:
Vibration Spectrum:
Microscopic picture of the atoms.
Conclusions:
In this lab various methods of spectroscopy were used to identify an unknown. Based on observations and analysis of the spectras the unknown of this lab was identified as Cyclohexanone.