C2.8 Instrumental Techniques

What is the x axis on a mass spectrum

mass/charge ratio

What is the y axis on a mass spectrum?

Either relative or percentage abundance

What is the x axis on an IR spectrum

wavenumber in cm⁻¹

What is the y axis on an IR spectrum

absorbance or transmittance

What is the x axis on an NMR spectrum?

chemical shift in ppm

What is the furthest (significant) peak to the right on a mass spectrum called?

The molecular ion (or M) peak.

What is the small peak next to the M peak called on a mass spectrum?

The M+1 peak

What is the base peak on a mass spectrum?

The highest peak in a mass spectrum, representing the most abundant ion detected.

What are the smaller parts of a larger molecule that has broken up in a mass spectrometer called?

Fragments

What is the region in an IR spectrum called below 1500cm^-1

The fingerprint region

What does the area under the peak in an ¹H NMR show?

The relative number of hydrogen ions in that environment

What does the area under a peak in C¹³ NMR tell you?

Nothing!

What do the number of peaks in either ¹H or ¹³C NMR tell you?

The number of distinct environments in the molecule