Here are the essential concepts you must grasp in order to answer the question correctly.
Infrared Spectroscopy (IR Spectroscopy)
Infrared spectroscopy is a technique used to identify and study chemicals based on their absorption of infrared light. Molecules absorb specific wavelengths of IR radiation, causing vibrations in their bonds. The resulting spectrum displays transmittance versus wavenumber, allowing chemists to deduce functional groups and molecular structures based on characteristic absorption peaks.
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Functional Groups
Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. Common functional groups include hydroxyl (-OH), carbonyl (C=O), and carboxylic acid (-COOH). Identifying these groups in an IR spectrum helps in determining the identity of the compound, as each group has distinct absorption patterns.
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Wavenumber
Wavenumber is a unit of measurement used in spectroscopy, defined as the number of wave cycles per unit distance, typically expressed in cm⁻¹. In IR spectroscopy, wavenumber is directly related to the energy of the absorbed light, with higher wavenumbers corresponding to higher energy vibrations. Analyzing the wavenumber values in an IR spectrum allows chemists to identify specific molecular vibrations and functional groups.