CHEM 140B Lecture Notes - Lecture 1: Spectroscopy, Organic Chemistry, Diamagnetism
5 Apr 2018
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Document Summary
Resonance (absorption of electromagnetic energy) at radio frequencies (rf) A technique for analyzing molecules based on how they absorb radiation. In organic chemistry, we use : nmr, ir, uv, ms for molecules identification. Organic molecules absorb energy in discrete packages called: quanta. Nuclei of atoms with an odd mass number or odd atomic number have nuclear spin. Diamagnetism: h nuclei in organic molecules experience a magnetic field beff which is less than the applied field, bo. Circulating electrons in lone pairs and covalent bonds induce an opposing magnetic field, Beff is the difference between bo and bind. The h nucleus is said to be shielded. The number of different signals indicates how many different nuclei are in a molecule and. The number of different signals indicates how many different nuclei are in a molecule and provides information about the overall symmetry of the molecule. In the h nmr the integration of peaks shows the relative amounts of protons/peak.
