Objectives
After completing this lab activity, you should be able to,
- Carry out a research-based experiments and identify unknown organic compounds.
- Identify the common organic compounds’ functional groups and determine the structure of an unknown compound using UV/Vis, IR, Mass, and NMR spectroscopes.
- Use Material Safety Data Sheets (MSDS) to obtain information such as molecular formula, physical properties, hazards, and disposal procedures for chemicals used in each experiment.
- Prepare and maintain a laboratory notebook, including a write-up of each experiment that details the purpose, chemical equations, calculation of theoretical yield, percent yield, and record of experimental observations.
- Write clear, concise, scientific laboratory reports using American Chemical Society style for each experiment.
- Use critical analysis skills to interpret data and draw conclusions.
LAB ACTIVITY
Answer all the questions and produce a lab report.
Q.1.Describe the vibrational frequencies for the carbonyl bands of IR spectra for the following compounds:
1. Acetophenone
2. Benzaldehyde
3. Benzamide
4. Benzoic acid
5. Benzoyl Chloride
6. Methyl Benzoate
Also, list the order of decreasing carbonyl frequency for the above compounds.
Q.2 Describe how IR carbonyl and specific other absorbances can distinguish propiophenone from 1-phenyl-2-propanone and p-ethylbenzaldehyde.
Q.3 Describe how utlraviolet (UV) spectroscopy could distinguish propiophenone from 1-phenyl-2-propanone and p-ethylbenzaldehyde. Consider their respective wavelengths at their maximum UV absorbances, (λ max).
ANSWER
Question 1
Describe the vibrational frequencies for the carbonyl bands or IR spectra for the following compounds;
- Acetophenone
- Benzaldehyde
- Benzamide
- Benzoic acid
- Benzoyl Cgloride
- Methyl Benzoate
Also, list the order of decreasing carbonyl frequency for the above compounds.
Answer
Methods and Analysis
Instruments used in measuring visible radiation and UV absorption entail the sources (visible or UV), detector, sample cells or sample containers, and monochromator or filter. UV radiation is an invisible type of electromagnetic radiation that has a wavelength of between 200nm and 400nm…..
Results
The vibrational frequency for any bond in IR spectra depends on the strength of that bond. For carbonyl group, the strength of the bond will influence the frequency of the spectra (Vogel & Houk, 2019). Notably, the stronger the bond, the more the IR frequency that is needed to vibrate the bond.
Usually, the stretching peaks for carbonyl group is between 1900cm-1 and 1600cm-1 (Vogel & Houk, 2019). For the……
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