Organic Synthesis, Nmr and Chromatography | AQA A-Level Chemistry (7405)
Organic Synthesis, Nmr and Chromatography
- 138 questions
- 9 subtopics
- Organic chemistry, examined on Paper 2
- Paper 2 and Paper 3
Organic synthesis, NMR and chromatography is examined on Papers 2 and 3, and pulls the whole organic course together.
It covers planning a multi-step route, the green chemistry that judges it, then NMR and the chromatography techniques used to separate and identify the products.
Sample questions from Organic Synthesis, Nmr and Chromatography
Answer each one closed book first, then open the answer.
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Multi-Step Synthesis Routes
When devising a multi-step synthesis, which reactions should you draw on?
Show the answer
Only reactions from the A-level course you have already met -
Green Chemistry Principles in Synthesis Design
Why do addition reactions have high atom economy?
Show the answer
All atoms from the reactants are incorporated into a single product with no by-products -
Principles of NMR and the Delta Scale
What symbol is used to represent chemical shift in NMR spectroscopy?
Show the answer
δ (delta) -
Carbon-13 NMR Interpretation
How can carbon-13 NMR be used to distinguish between structural isomers?
Show the answer
Different structural isomers have different numbers and/or positions of carbon environments, giving different numbers of peaks -
Proton NMR Chemical Shift and Integration
What compound is used as a standard reference in NMR spectroscopy?
Show the answer
Tetramethylsilane (TMS) -
Spin-Spin Splitting and the n+1 Rule
What splitting pattern does a proton show when it has three adjacent non-equivalent protons?
Show the answer
A quartet (4 peaks). -
TMS and Deuterated Solvents
Why is the chemical shift of TMS defined as zero on the δ scale?
Show the answer
TMS is used as the reference standard against which all other chemical shifts are measured -
Thin-Layer Chromatography and Rf Values
How is the Rf value calculated?
Show the answer
Rf = distance travelled by substance ÷ distance travelled by solvent front.
The 9 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Multi-Step Synthesis Routes | Planning a route between two compounds, and choosing the reagents and conditions for each step. | 20 |
| Green Chemistry Principles in Synthesis Design | Atom economy, waste, solvents and energy, and how they shape the route chosen. | 13 |
| Principles of NMR and the Delta Scale | How nuclei absorb radio frequency in a magnetic field, chemical shift, and shielding. | 16 |
| Carbon-13 NMR Interpretation | Counting carbon environments, and using them to tell isomers apart. | 12 |
| Proton NMR Chemical Shift and Integration | Reading chemical shift from a data sheet, and what integration ratios tell you. | 17 |
| Spin-Spin Splitting and the n+1 Rule | Why peaks split, applying the n+1 rule, and naming the splitting patterns. | 13 |
| TMS and Deuterated Solvents | Why TMS is the reference, and why the solvent must contain no ordinary hydrogen. | 14 |
| Thin-Layer Chromatography and Rf Values | The stationary and mobile phases, calculating Rf, and identifying a spot. | 15 |
| Column and Gas Chromatography, and GC-MS | Stationary and mobile phases, retention time, and coupling gas chromatography to a mass spectrometer. | 18 |
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
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Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
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Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
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Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Nearby topics
AQA A-Level Chemistry Active Recall Guide
Every topic, not just this one. 2,442 questions with their answers.