1057-RG_12-09 - Chem 1057 J. Walcott LEARNING STRATEGIES...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Chem 1057 J. Walcott LEARNING STRATEGIES CENTER Fall 2009 Review Guide #12 Lectures: 11/23/09 – 12/4/09: Chapters 11 and 13 I. Unsaturation Units: To determine a possible structure of an unknown compound, it is useful to find the unsaturation units. U = C + 1 – 1/2 ( X- N) where C = # of carbons (tetravalent atoms), X = # of H and halogens (monovalent atoms) and N = # of nitrogens (trivalent) atoms. When U = 1, a ring or 1 double bond is possible. When U = 2, a ring and a double bond, 2 rings, 2 double bonds or a triple bond are possible etc. II. Nuclear Magnetic Resonance (NMR) Spectroscopy A. When certain nuclei are placed in a strong magnetic field, their spins cause them to behave like tiny magnets (magnetic dipoles) which orient either with or against the field. The nuclei with magnetic dipoles aligned parallel to the applied field are lower in energy, and those with magnetic dipoles aligned antiparallel to the applied field are higher in energy. If the sample is subjected to electromagnetic radiation equal to this energy difference, energy can be absorbed by nucei in the lower energy state causing the nuclei to invert or “flip” their spins. The energy difference,
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 2

1057-RG_12-09 - Chem 1057 J. Walcott LEARNING STRATEGIES...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online