A LevelChemistryAQARevision NotesAdvanced Organic ChemistryNuclear Magnetic Resonance SpectroscopyPrinciples of NMR

Principles of NMR (AQA A Level Chemistry): Revision Note

Exam code: 7405

Stewart Hird

Written by: Stewart Hird

Reviewed by: Caroline Carroll

Updated on

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)

Examiner Tips and Tricks

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

Unlock more, it's free!

Join the 100,000+ Students that ❤️ Save My Exams

the (exam) results speak for themselves:

I would just like to say a massive thank you for putting together such a brilliant, easy to use website.I really think using this site helped me secure my top gradesin science and maths. You really did save my exams! Thank you.

Beth
IGCSE Student

This website is soooo useful and I can’t ever thank you enough for organising questions by topic like this. Furthermore, the name of the website could not have been more appropriate as it literally did SAVE MY EXAMS!

Fathima
A Level Student

Incredible! SO worth my money, the revision notes have everything I need to know and are so easy to understand. I actually enjoy revising! It makes me feel a lot more confident for my GCSEs in a few months.

Kate
GCSE Student

Absolutely brilliant, both my girls used it for A levels and GCSE. It's saves on paper copies, also beneficial exam questions ranked from easy to hard. It's removed a lot of stress from the exams.

Sameera
Parent

Just to say that your resources are the best I have seen and I have been teaching chemistry at different levels for about 40 years

Mark
Chemistry Teacher

Excellent

Our rating represented in Trustpilot stars
Read more reviews

Build on this topic

Check your understandingTry an Exam Question on this topicLearn at your levelTake a Smart Lesson that adapts to your performance
Previous:Organic MechanismsNext:¹H NMR
Author
Reviewer
Stewart Hird

Author: Stewart Hird

Expertise: Chemistry Content Creator

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.

Caroline Carroll

Reviewer: Caroline Carroll

Expertise: Head of Content Delivery

Caroline graduated from the University of Nottingham with a degree in Chemistry and Molecular Physics. She spent several years working as an Industrial Chemist in the automotive industry before retraining to teach. Caroline has over 12 years of experience teaching GCSE and A-level chemistry and physics. She is passionate about delivering high-quality resources to help students achieve their full potential.