CHEM 211 Lecture Notes - Lecture 22: Molar Mass
4 Nov 2016
School
Department
Course
Professor
Document Summary
Interpretation of 13c nmr spectra: only 1. 1% of carbons are nmr active, because most are found in 12c form. 3 differences: need more sample for 13c nmr, scale is different. 13c chem shifts: decreased electron density = deshielding. More down eld: increased electron density = shielding. Dept techniques: helps distinguish between primary, secondary, etc. carbons. See how different proton nmrs and see how they"re similar: hecto. Sees how two different proton nmrs are different. Mass spectrometry: gives us the mass of the compound. Helps you generate a formula by giving you the molecular weight: the largest peak is the molar mass of the compound. This is called the parent peak: also called m+ peak, fragments = pieces of the molecules that result from bond breakage. Change in number from the parent peak to the fragments is the molecular weight: ex. 14 = ch2, 15 = ch3, 29 = ch2ch3, 91 = aromatic: base peak is the biggest peak.
