Infrared Spectroscopy

Question 1

What does the amount that a bond stretches or bends depend upon?

Answer 1

1. The mass of the atoms
   —> the heavier the atom, the slower the vibrations
2. The bond strength
   —> stronger bonds vibrate faster

Question 2

How is infrared spectroscopy used to identify functional groups?

Answer 2

1. Sample is placed inside IR spectrometer
2. A beam of IR radiation is passed through the sample
3. The molecule absorbs some of the IR frequencies, and the emerging beam of radiation is analysed to identify which frequencies have been absorbed

Question 3

Where is the fingerprint region found?

Answer 3

Below 1500cm-1

Question 4

What steps do you follow to analyse an IR spectrum?

Answer 4

1. Remove fingerprint region
2. Identify if C-H peak is present
3. Identify any other functional group peaks

Question 5

What are some applications of Infrared Spectroscopy?

Answer 5

• forensic science
• quality control in manufacturing
• drug analysis