INFRARED SPECTROSCOPY II – QUALITATIVE IDENTIFICATION 1. What is the usual way t
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Question
INFRARED SPECTROSCOPY II – QUALITATIVE IDENTIFICATION
1. What is the usual way the IR chart is displayed?
2. Are there others? What are they? When are they employed?
3. Can you perform Quantitative analysis by IR? How? What difficulties will you encounter? How will you deal with these?
4. When analyzing your unknown, what information will you wish to obtain from the IR spectrum?
5. How will you identify you r unknown? Be specific concerning the steps.
6. Explain DRIFTS and ATR sampling methods.
7. Are any corrections necessary to be performed on ATR spectra? Why?
Explanation / Answer
1. The infrared spectrum displays absorption as inverted peaks on a linear frequency scale. The top represents 100% transmission and the bottom represents no transmission. Thus if a sample has 100% transmission, there will be a horizontal line which suggests that the compound did not absorb at all. The frequency scale is given as cm-1 instead of Hz, because the resulting numbers can be easily managed.