WJEC A-Level Chemistry AS Unit 2, June 2025
Every question from WJEC A-Level Chemistry AS Unit 2, June 2025 (2410): 11 questions, 80 marks, each with its mark scheme and topic.
- Question 1 1 mark
Draw the skeletal formula of pentane-2,4-diol.
Organic Chemistry · 2.4 Organic compounds · 2.7 Alcohols and carboxylic acids
- Question 2 1 mark
Name the straight-chain alkane that has the same molecular formula as 2,2,4-trimethylpentane.
Organic Chemistry · 2.4 Organic compounds
- Question 3 2 marks
Draw a Boltzmann distribution curve at a lower temperature and state how a catalyst increases reaction rate.
Physical Chemistry · 2.2 Rates of reaction
- Question 4 2 marks
Complete the diagram to show the mechanism for the nucleophilic substitution of bromoethane to form ethanol, including relevant dipoles and curly arrows.
Organic Chemistry · 2.4 Organic compounds · 2.6 Halogenoalkanes
- Question 5 2 marks
Name the given alkene using IUPAC nomenclature including stereochemical descriptor.
Organic Chemistry · 2.4 Organic compounds
- Question 6 2 marks
Deduce standard enthalpy changes for reverse and coupled reactions using given thermochemical equations.
Physical Chemistry · 2.1 Thermochemistry
- Question 7 10 marks
Describe the mechanism of free-radical substitution of methane with chlorine, explain the formation of side-products, and evaluate reaction conditions to optimize the yield of chloromethane.
Organic Chemistry · 2.5 Hydrocarbons
- Question 8 17 marks
Investigate the endothermic reaction between hydrated barium hydroxide and ammonium chloride by completing a reaction profile, calculating enthalpy change of formation, plotting experimental temperature data, and determining experimental enthalpy change.
Physical Chemistry · Practical · 2.1 Thermochemistry · 1.3 Chemical calculations · AS Unit 2 practical work
- Question 9 18 marks
Determine the identity of an unknown organic compound from analytical spectra and elemental analysis, and answer questions on the oxidation and esterification reactions of propan-1-ol and propanoic acid.
Organic Chemistry · Physical Chemistry · 2.8 Analysis of organic compounds · 2.7 Alcohols and carboxylic acids · 1.3 Chemical calculations · 1.1 Formulae and equations
- Question 10 11 marks
Describe the elimination of halogenoalkanes, draw the mechanism for electrophilic addition of hydrogen bromide to an alkene, and explain major product formation via carbocation stability.
Organic Chemistry · 2.4 Organic compounds · 2.5 Hydrocarbons · 2.6 Halogenoalkanes
- Question 11 14 marks
Analyse experimental data for the hydrolysis of halogenoalkanes using colorimetry and describe an iodine clock method to determine the effect of concentration on reaction rate.
Organic Chemistry · Physical Chemistry · Practical · 2.6 Halogenoalkanes · 2.2 Rates of reaction · AS Unit 2 practical work