VIMAL SIEWNARINE - #52844
JASON MATHURA - #60927
FIDEL MENDOZA- #56834
BRAD NANDO- #
VIMAL BALAY - #52555
CRISTINA LUTCHMAN -#52516
LAB #1, #2, #3, #4
CHEM 2006 -ANALYTICAL INSTRUMENTATION
LECTURER – MRS. TRICIA JONES
TITLE: Organic Compound Identification Using Infrared Spectroscopy Aim: To identify the functional groups in organic compounds using infrared spectra. APPARATUS AND REAGENTS:
HATR Accessory (liquid crystal plates)
Reagents ( Methanol, Benzene and Cyclohexane, Cyclohexene)
An important tool of the organic chemist is Infrared Spectroscopy, or "IR". IR spectra are acquired on a special instrument, called an IR spectrometer. IR is used to gather information about compound's structure, assess its purity, and sometimes to identify it. Infrared radiation is that part of the electromagnetic spectrum between the visible and microwave regions. Infrared radiation is absorbed by organic molecules and converted into energy of molecular vibration, either stretching or bending. Different types of bonds, and thus different functional groups, absorb infrared radiation of different wavelengths. An IR spectrum is a plot of wavenumber (X-axis) vs percent transmittance (Y-axis). Most functional groups give rise to bands in particular regions of the spectrum. The region from 4000-1300 cm-1 is particularly useful for identifying the presence of specific functional groups.
As seen in lab script.
There were three unknowns that were identified. These were unknown A, unknown B and unknown C. 1. Unknown A – Benzene (C6H6)- The aromatic CH stretch appears at 3100 -3000 cm-1 and the CC stretch is at about 1500 cm-1. This will be shown on the waveform.
2. Unknown B – Cyclohexene (C6H10) - The main band is a strong CH stretch from CH2 groups at about 3000 cm-1. The CH2 bend appears at about 1450 cm-1. The CH stretch for the alkene is to the left of 3000 cm-1. The weaker bands are in the range of 1000 – 650 cm-1 This is shown on the waveform
3. Unknown C – Methanol – The important observation that was made was the OH stretch appeared as a broad band at approximately 3300 – 3500 cm-1. Shown in the waveform
The functional groups in organic compounds were successfully identified using Infrared Spectroscopy.
To determine the weight percent of copper in an unknown compound using spectrophotometry. To explore the technique of spectrophotometry, the use of light to determine property of a substance. APPARATUS-
Distilled water(wash bottle)
Dual beam UV-VIS spectrophotometer
Many molecules absorb ultraviolet or visible light. The absorption of UV or visible radiation by an atom or molecule corresponds to the excitation of outer electrons (electrons are promoted from their ground state to an excited state). In order to determine the concentration of copper in the unknown solution, a standard plot of concentration of copper vs. the absorbance of solutions having known copper concentrations. According to Beer’s law, absorbance is directly proportional to concentration and so the resulting plot should be a straight line. This graph could be used to determine the concentrations of solutions containing known amounts of the unknown copper compound and from this we can determine the weight percent of copper. PROCEDURE-
As seen in lab script
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