AQA A Level Chemistry

Revision Notes

7.10.1 Principles of NMR

Test Yourself

Principles of NMR

  • Nuclear Magnetic Resonance (NMR) spectroscopy is used for analysing organic compounds
  • NMR analysis can provide information about the positions of 13C and 1H atoms in a molecule
  • All samples are measured against a reference compound – Tetramethylsilane (TMS)
    • TMS shows a single sharp peak on NMR spectra, at a value of zero
    • Sample peaks are then plotted as a ‘shift’ away from this reference peak
    • This gives rise to ‘chemical shift’ values for protons on the sample compound
    • Chemical shifts are measured in parts per million (ppm)

Exam Tip

You are often asked in exam questions why tetramethylsilane (TMS) is a suitable solvent for NMR analysis. Try to remember that TMS is:

  • Non toxic.
  • Does not react with the sample.
  • Easily separated from the sample molecule due to its low boiling point.
  • Produces one strong, sharp absorption peak on the spectrum.

Worked example

Draw the structural formula of TMS

Answer:

Structural formula of TMS, downloadable AS & A Level Chemistry revision notes

You've read 0 of your 0 free revision notes

Get unlimited access

to absolutely everything:

  • Downloadable PDFs
  • Unlimited Revision Notes
  • Topic Questions
  • Past Papers
  • Model Answers
  • Videos (Maths and Science)

Join the 80,663 Students that ❤️ Save My Exams

the (exam) results speak for themselves:

Did this page help you?

Stewart

Author: Stewart

Stewart has been an enthusiastic GCSE, IGCSE, A Level and IB teacher for more than 30 years in the UK as well as overseas, and has also been an examiner for IB and A Level. As a long-standing Head of Science, Stewart brings a wealth of experience to creating Topic Questions and revision materials for Save My Exams. Stewart specialises in Chemistry, but has also taught Physics and Environmental Systems and Societies.