IR Spectroscopy Worksheet
A Grade 11 Science worksheet covering the fundamentals of Infrared (IR) Spectroscopy, including principles, functional group identification, and spectrum analysis.
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IR Spectroscopy Worksheet
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Read each question carefully and provide clear, concise answers. For questions requiring spectrum analysis, assume standard IR ranges for functional groups.
1. Which of the following best describes the principle behind IR spectroscopy?
Absorption of radio waves by atomic nuclei
Excitation of electrons to higher energy levels
Vibrational excitation of molecular bonds
Rotation of molecules in an electric field
2. A strong, broad absorption band around 3300 cm⁻¹ in an IR spectrum typically indicates the presence of which functional group?
Carbonyl (C=O)
Alkene (C=C)
Hydroxyl (O-H)
Alkyne (C≡C)
3. IR spectroscopy measures the absorption of infrared radiation by molecular .
4. The region of an IR spectrum from approximately 1500 cm⁻¹ to 400 cm⁻¹ is known as the region, which is unique for most compounds.
5. Briefly explain why a molecule must have a change in dipole moment during a vibration to be IR active.
6. All covalent bonds absorb IR radiation.
True
False
Match the typical IR absorption range with its corresponding functional group.
7. 1700 cm⁻¹
a. C≡C (Alkyne)
8. 2100-2260 cm⁻¹
b. C=O (Carbonyl)
9. 3000-3100 cm⁻¹
c. C-H (Alkane)
10. 2850-2960 cm⁻¹
d. C-H (Alkene)
11. An unknown organic compound shows a strong, sharp absorption at 1715 cm⁻¹ and no significant absorption above 3000 cm⁻¹. Based on this information, propose a possible functional group present in the compound and explain your reasoning.