Analysis II

Question 1

How to identify the molecular ion peak in a mass spectrum

Answer 1

Peak that is furthest to the right (ignoring very small peaks due to alternative isotopes)

Question 2

How to identify the base peak in a mass spectrum

Answer 2

Highest peak (most abundant fragment)

Question 3

In chromatography, what is the difference between an Rf value and an Rt value?

Answer 3

An Rf value (the retention factor) in paper chromatography or TLC is the distance travelled by a component relative to the solvent front, whereas an Rt value (the retention time) in column chromatography is the time taken for a component to pass through the column.

Question 4

How to determine number of C environments from an NMR spectrum

Answer 4

Number of peaks (ignoring any ‘peak splitting’)

Question 5

Which wavenumber range is most useful for identifying bonds using IR?

Answer 5

Above wavenumbers of 1500cm^-1

Question 6

How to determine the number of C atoms in a particular environment from an NMR spectrum

Answer 6

Relative peak height or peak area (often called an integral)