AQA A-Level Chemistry 7405
Atomic Structure
Amount of Substance
Bonding
Energetics and Thermodynamics
Kinetics
Chemical Equilibria
Redox and Electrochemistry
Acids and Bases
Periodicity and Group Chemistry
Period 3 Elements and Their Oxides
Transition Metals
Introduction to Organic Chemistry
Hydrocarbons
Halogenoalkanes, Alcohols and Organic Analysis
Carbonyls, Carboxylic Acids and Derivatives
Aromatic Chemistry and Amines
Polymers, Amino Acids, Proteins and DNA
Organic Synthesis, NMR and Chromatography
Organic Synthesis, NMR and Chromatography
TMS and Deuterated Solvents
- 3 things to know
- Papers 2 and 3
Overview
Why TMS is the reference, and why the solvent must contain no ordinary hydrogen.
What you need to know
Answer each one before you reveal it.
Why does TMS produce a single sharp peak in both ¹H NMR and ¹³C NMR spectra?
Why is the chemical shift of TMS defined as zero on the δ scale?
Questions from this subtopic
Each one with the model answer underneath.
- 1
What compound is used as the reference standard in NMR spectroscopy?
Model answer
Tetramethylsilane (TMS)
- 2
What is the chemical name for TMS?
Model answer
Tetramethylsilane
- 3
What is the molecular formula of TMS?
Model answer
Si(CH₃)₄ or C₄H₁₂Si
- 4
Why does TMS produce a single sharp peak in both ¹H NMR and ¹³C NMR spectra?
Model answer
All twelve hydrogen atoms are in identical chemical environments, and all four carbon atoms are in identical chemical environments
- 5
Why is the chemical shift of TMS defined as zero on the δ scale?
Model answer
TMS is used as the reference standard against which all other chemical shifts are measured
- 6
Why is TMS chemically inert and unlikely to react with the sample being analysed?
Model answer
The silicon-carbon bonds are strong and TMS has no functional groups that would react with typical organic samples
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