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Unit 4: Organic Chemistry and Analysis

8 dot points across 8 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do alcohols and phenols differ in their reactions?

The reactions of alcohols, oxidation and dehydration, the acidity and characteristic reactions of phenols, and tests to distinguish them.
A focused answer to WJEC A-Level Chemistry Unit 4, covering the reactions of alcohols including oxidation and dehydration, the weak acidity and ring reactions of phenols, and chemical tests that distinguish alcohols from phenols.
12 min answer →

How do carbonyl compounds react and how do we tell them apart?

The carbonyl group, nucleophilic addition, reduction and oxidation of aldehydes and ketones, and tests to identify and distinguish them.
A focused answer to WJEC A-Level Chemistry Unit 4, covering the carbonyl group, nucleophilic addition of cyanide and reduction, the oxidation of aldehydes, and the chemical tests that identify carbonyls and distinguish aldehydes from ketones.
12 min answer →

How do nitrogen-containing organic molecules behave?

The preparation and basicity of amines, the properties of amino acids and zwitterions, peptide bonds, and the formation of polyamides and proteins.
A focused answer to WJEC A-Level Chemistry Unit 4, covering the preparation and basicity of amines, the zwitterionic behaviour and isoelectric point of amino acids, peptide bonds, and the formation of polyamides and proteins.
12 min answer →

Why is benzene so stable and how does it react?

The structure and stability of benzene, the delocalised model, electrophilic substitution reactions, and the reactions of phenol.
A focused answer to WJEC A-Level Chemistry Unit 4, covering the delocalised structure and stability of benzene, the evidence from enthalpies of hydrogenation, electrophilic substitution mechanisms (nitration and halogenation), and the reactivity of phenol.
12 min answer →

How do carboxylic acids and their derivatives react?

Carboxylic acids and their acidity, esters, acyl chlorides and acid anhydrides, and the reactions and interconversions of these derivatives.
A focused answer to WJEC A-Level Chemistry Unit 4, covering the acidity and reactions of carboxylic acids, esters, acyl chlorides and acid anhydrides, and how these derivatives interconvert and react with nucleophiles.
12 min answer →

How do we plan a multi-step synthesis and check the product?

Reaction pathways linking functional groups, planning multi-step syntheses, practical techniques of preparation and purification, and assessing purity.
A focused answer to WJEC A-Level Chemistry Unit 4, covering reaction pathways linking functional groups, planning multi-step syntheses, the practical techniques of preparation and purification, and assessing the purity of a product.
12 min answer →

How do we determine the structure of an unknown molecule?

Mass spectrometry, infrared spectroscopy, proton and carbon-13 NMR, and chromatographic separation in structure determination.
A focused answer to WJEC A-Level Chemistry Unit 4, covering mass spectrometry and fragmentation, infrared spectroscopy, proton and carbon-13 NMR, and chromatographic separation in determining the structure of organic molecules.
12 min answer →

How can molecules with the same formula differ in three dimensions?

E/Z isomerism, optical isomerism and chirality, the rotation of plane-polarised light, racemic mixtures, and the importance of stereochemistry in drugs.
A focused answer to WJEC A-Level Chemistry Unit 4, covering E/Z and optical isomerism, chirality and chiral centres, the rotation of plane-polarised light, racemic mixtures, and the importance of stereochemistry in pharmaceuticals.
11 min answer →