A mass spectrometer is able to very accurately determine the relative atomic mass of an element by measuring the mass and abundance each of the isotopes of an element in a sample (and this may vary depending on where the element sample has come from). We can also use the technique to help identify organic molecules.
Here you will find links to everything you need to know for A level Chemistry 😊.
The time of flight mass spectrometer
• what is a time of flight mass spectrometer?
• how is the kinetic energy of an ion related to its mass or velocity?
• how do I calculate the time taken for an ion to travel the length of the flight tube?
Calculating the relative atomic mass of an element from a mass spectrum
We know from GCSE that the relative atomic mass (Ar) is the average of (% abundance of an isotope x isotopic mass) for each of the isotopes in a sample of an element – the next step is to calculate Ar directly from a mass spectrum …
Calculating the relative abundance of isotopes for an element
We can calculate the percentage abundances for each of the isotopes in an element if we know the mass number for each isotope and the Ar …
How to interpret the mass spectrum of an organic molecule
Mass spectrometry is a really powerful tool for helping us to piece together the structure of an organic molecule.
Ionisation of molecules causes them to fragment and these ionised fragments are recorded as peaks on the mass spectrum.
Mixed spectra long answer questions
This is a set of more difficult long answer exam questions that require you to use data from mass spectra, IR spectra, 1H NMR and 13C NMR spectra to deduce the structure of a molecule.
They are notoriously poorly answered by students, so hopefully the model answers and exam tips here will help you power through!