Interpreting an IR(infrared spectrum) Spectrum

Question 1

Infrared (IR) spectroscopy is a technique used to

Answer 1

identify compounds based on changes in vibrations of atoms when they absorb IR of certain frequencies

Question 2

A spectrophotometer irradiates the

Answer 2

sample with electromagnetic waves in the infrared region and then detects the intensity of the wavelength of IR radiation which goes through the sample

Question 3

All organic molecules absorb IR radiation and depending on which energies of radiation are absorbed, bonds between atoms will vibrate by

Answer 3

stretching, bending and twisting

Question 4

The molecules will only vibrate at a specific frequency
The resonance frequency is the

Answer 4

specific frequency at which the molecules will vibrate to stimulate larger vibrations

Question 5

Depending on the rest of the molecule, each vibration will absorb specific wavelengths of IR radiation which are also shown as the

Answer 5

reciprocal of the wavelength

Question 6

IR radiation wavelengths measurements

Answer 6

wavenumber (cm-1)

Question 7

Particular absorbance have characteristic

Answer 7

widths (broad or sharp) and intensities (strong or weak)
For example, hydrogen bonds cause the O-H bonds in alcohols and carboxylic acids to be broad whereas the C-O bond in carbonyl (C=O) groups have a strong, sharp absorbance peak

Question 8

Due to some absorption bands overlapping each other, other analytical techniques such as

Answer 8

mass spectroscopy should be used alongside IR spectroscopy to identify an unknown compound