WJEC A-Level Chemistry Unit 4, June 2025
Every question from WJEC A-Level Chemistry Unit 4, June 2025 (1410): 9 questions, 80 marks, each with its mark scheme and topic.
- Question 1 4 marks
State the reagents for nitrating aromatic hydrocarbons, explain the effect of impurities on melting point, and calculate the moles of gaseous products from TNT decomposition.
Organic Chemistry · Physical Chemistry · Practical · 4.2 Aromaticity · 4.8 Organic synthesis and analysis · 1.3 Chemical calculations · A2 Unit 4 practical work
- Question 2 2 marks
State the observation when propan-2-ol reacts with an alkaline solution of iodine and draw the structure of the product formed when it is oxidized by acidified potassium dichromate.
Organic Chemistry · 2.7 Alcohols and carboxylic acids · 4.4 Aldehydes and ketones
- Question 3 2 marks
Calculate the mass of water required to react with bis(2-chloroethyl) sulfide and deduce the products from a nucleophilic substitution mechanism step.
Physical Chemistry · Organic Chemistry · 1.3 Chemical calculations · 2.4 Organic compounds · 2.6 Halogenoalkanes
- Question 4 2 marks
Explain why 4-bromophenol reacts with sodium hydroxide and why the bromine atom is not replaced by a hydroxyl group.
Organic Chemistry · 4.3 Alcohols and phenols · 4.2 Aromaticity · 2.6 Halogenoalkanes
- Question 5 14 marks
Determine the identity and structure of compounds derived from 4-hydroxycinnamic acid using titration data, percentage composition, polymerisation, and explain trends in boiling temperatures of aromatic compounds.
Organic Chemistry · Physical Chemistry · 1.3 Chemical calculations · 1.4 Bonding · 2.5 Hydrocarbons · 4.2 Aromaticity · 4.3 Alcohols and phenols · 4.5 Carboxylic acids and their derivatives · 4.8 Organic synthesis and analysis
- Question 6 16 marks
Deduce mechanisms, equations, and carry out calculations relating to chlorination of alkanes and methylbenzene, including ideal gas, atom economy, and titration calculations.
Organic Chemistry · Physical Chemistry · Practical · 1.3 Chemical calculations · 2.2 Rates of reaction · 2.5 Hydrocarbons · 4.5 Carboxylic acids and their derivatives · AS Unit 1 practical work · AS Unit 2 practical work
- Question 7 15 marks
Devise a method to obtain pure benzoic acid crystals from contaminated sodium benzoate, determine the identity of an aromatic amine via gas calculations and NMR spectroscopy, name an azo dye component, and identify isomers based on characteristic chemical tests.
Organic Chemistry · Physical Chemistry · Practical · 1.3 Chemical calculations · 4.4 Aldehydes and ketones · 4.5 Carboxylic acids and their derivatives · 4.6 Amines · 4.8 Organic synthesis and analysis · A2 Unit 4 practical work
- Question 8 13 marks
Deduce mechanisms and equations for the synthesis and reactions of 2-aminopropanoic acid, identify amino acid structures and protein secondary structure, and calculate enantiomeric composition and yield from plant sources of L-dopa.
Organic Chemistry · Physical Chemistry · 1.3 Chemical calculations · 2.3 The wider impact of chemistry · 2.5 Hydrocarbons · 2.6 Halogenoalkanes · 4.1 Stereoisomerism · 4.5 Carboxylic acids and their derivatives · 4.7 Amino acids, peptides and proteins
- Question 9 12 marks
Identify reagents and reaction types in aromatic carboxylic acid and amide syntheses, deduce the structure of a degradation product from spectroscopic data, and determine an unknown alkyl group via titration.
Organic Chemistry · Physical Chemistry · 4.5 Carboxylic acids and their derivatives · 4.6 Amines · 2.8 Analysis of organic compounds · 1.3 Chemical calculations