Chapter 16, Problem 16.76P

Interpretation Introduction

(a)

Interpretation:

The formula of a compound that can produce the given mass spectrum is to be determined.

Concept introduction:

The mass spectrum of a compound is often represented as a bar graph with m/z on the x axis (where m is in atomic mass units, u) and the relative abundance of ions at each m/z on the y axis. The mass of each ion is just the mass of the atoms that make it up. The ${\text{M}}^{\text{+}}$ peak of a mass spectrum is taken to be the compound’s molecular mass. From the ratio of the ${\text{M}}^{\text{+}}$ and $\text{M + 1}$ peak intensities, the number of carbon atoms is calculated. The masses of the C atoms and the heteroatoms are subtracted from the molecular mass. The remaining mass reasonably is made up by hydrogens. If that number of H atoms is unreasonably high, then consider adding another non-hydrogen atom to the formula.

Interpretation Introduction

(b)

Interpretation:

The formula of a compound that can produce the given mass spectrum is to be determined.

Concept introduction:

The mass spectrum of a compound is often represented as a bar graph with m/z on the x axis (where m is in atomic mass units, u) and the relative abundance of ions at each m/z on the y axis. The mass of each ion is just the mass of the atoms that make it up. The ${\text{M}}^{\text{+}}$ peak of a mass spectrum is taken to be the compound’s molecular mass. From the ratio of the ${\text{M}}^{\text{+}}$ and $\text{M + 1}$ peak intensities, the number of carbon atoms is calculated. The masses of the C atoms and the heteroatoms are subtracted from the molecular mass. The remaining mass reasonably is made up by hydrogens. If that number of H atoms is unreasonably high, then consider adding another non-hydrogen atom to the formula.