Identifying compounds from infrared and mass spectra (A level)

A set of five problems to practise identifying organic compounds from % composition, infrared (IR) spectroscopy and mass spectrometry. Suitable for AS or A2 level, this type of exercise is good preparation for exam questions on identifying organic compounds using combined spectroscopic techniques. It could also be used for revision or consolidation of IR spectroscopy and mass spectrometry, as well as for assessment for learning.
Full answers to all the problems are provided.

This resource was developed primarily for the OCR A level Chemistry specification but is useful for all specifications. It relates to the following sections :
AS: Module 4 – Core organic chemistry
Part 2 – Alcohols, haloalkanes and analysis
4.2.4 Analytical techniques
A2: Module 6 – Organic chemistry and analysis
Part 3 – Analysis
6.3.2 Spectroscopy (Combined techniques)

Please review!

Content covered
• Calculating empirical formula from % composition
• Calculating molecular formula from empirical formula and molar mass, using the molecular ion peak on the mass spectrum
• Using the infrared (IR) spectrum to identify bond stretches and hence functional group(s) present
• Drawing structural formulae consistent with the molecular formula and IR data
• Using mass spectrum to distinguish between the suggested structural formulae
• Identifying fragments in the mass spectrum

Duration: 1 part lesson and/or independent study

Links
Please see also:
infrared (IR) spectroscopy - A level
https://www.tes.com/teaching-resource/infrared-ir-spectroscopy-a-level-home-learning-self-study-12315096
mass-spectrometry - A level
https://www.tes.com/teaching-resource/mass-spectrometry-a-level-home-learning-self-study-12287938
mass spectrometry summary AS home learning
https://www.tes.com/teaching-resource/mass-spectrometry-summary-as-home-learning-coronavirus-12287495