Organic Chemistry

Worked examples (5)

• 1Define a homologous series and identify members (5 marks, Paper 1)
• 2Draw and name the isomers of butane (5 marks, Paper 1)
• 3Test for unsaturation using bromine water (5 marks, Paper 1)
• 4Naming organic compounds — prefix and suffix (4 marks, Paper 1)
• 5Saturated vs unsaturated — definition and reactions (5 marks, Paper 1)

Model answers (4)

• ✓Model answer — 4CH1/1C-style — homologous series features
• ✓Model answer — 4CH1/1C-style — isomerism of pentane
• ✓Model answer — 4CH1/1C-style — bromine water test for unsaturation
• ✓Model answer — 4CH1/2C-style — homologous series overview

Worked examples (5)

• 1Describe fractional distillation of crude oil (6 marks, Paper 1)
• 2Cracking — purpose and equations (5 marks, Paper 1)
• 3Why bp increases down the column (4 marks, Paper 1)
• 4Environmental impact of pollutants from fossil-fuel combustion (5 marks, Paper 1)
• 5Complete vs incomplete combustion (5 marks, Paper 1)

Model answers (4)

• ✓Model answer — 4CH1/2C-style — fractional distillation full description
• ✓Model answer — 4CH1/2C-style — cracking detailed
• ✓Model answer — 4CH1/2C-style — air pollution from fuels
• ✓Model answer — 4CH1/2C-style — cracking equations

Worked examples (5)

• 1State the general formula of alkanes and name the first four members (4 marks, Paper 1)
• 2Complete vs incomplete combustion of propane (5 marks, Paper 1)
• 3Methane + chlorine in UV light — substitution reaction (5 marks, Paper 2)
• 4Isomers of butane — draw and name (4 marks, Paper 1)
• 5Why alkanes are relatively unreactive (4 marks, Paper 2)

Model answers (4)

• ✓Model answer — 4CH1/1C-style — alkane series overview
• ✓Model answer — 4CH1/1C-style — methane combustion
• ✓Model answer — 4CH1/2C-style — bromination of methane
• ✓Model answer — 4CH1/1C-style — alkane vs alkene comparison

Worked examples (5)

• 1Define the alkene homologous series and give first three members (4 marks, Paper 1)
• 2Test for unsaturation — bromine water (5 marks, Paper 1)
• 3Hydrogenation of ethene + industrial application (5 marks, Paper 1)
• 4Industrial ethanol from ethene — hydration (6 marks, Paper 1)
• 5Propene + bromine — equation and naming (4 marks, Paper 1)

Model answers (4)

• ✓Model answer — 4CH1/1C-style — alkene series overview
• ✓Model answer — 4CH1/2C-style — alkene addition reactions
• ✓Model answer — 4CH1/2C-style — industrial ethanol manufacture
• ✓Model answer — 4CH1/1C-style — alkane vs alkene with bromine

Worked examples (5)

• 1Define the alcohol homologous series and give first three members (4 marks, Paper 1)
• 2Fermentation of glucose by yeast — equation and conditions (5 marks, Paper 1)
• 3Compare hydration of ethene vs fermentation (6 marks, Paper 2)
• 4Oxidation of ethanol to ethanoic acid — colour change (5 marks, Paper 2)
• 5Propan-1-ol and its isomer propan-2-ol (3 marks, Paper 1)

Model answers (5)

• ✓Model answer — 4CH1/2C-style — fermentation of glucose
• ✓Model answer — 4CH1/2C-style — ethanol manufacture comparison
• ✓Model answer — 4CH1/2C-style — ethanol oxidation
• ✓Model answer — 4CH1/2C-style — bioethanol sustainability
• ✓Model answer — 4CH1/1C-style — alcohol uses

Worked examples (5)

• 1Define the carboxylic acid homologous series and give first three members (4 marks, Paper 1)
• 2Reaction of ethanoic acid with magnesium — observations and equation (5 marks, Paper 1)
• 3Ethanoic acid + sodium carbonate (4 marks, Paper 1)
• 4Ethanoic acid + sodium hydroxide — neutralisation (3 marks, Paper 1)
• 5Why ethanoic acid is a WEAK acid (4 marks, Paper 2)

Model answers (4)

• ✓Model answer — 4CH1/1C-style — ethanoic acid + magnesium
• ✓Model answer — 4CH1/2C-style — strong vs weak acid
• ✓Model answer — 4CH1/2C-style — neutralisation + salt preparation
• ✓Model answer — 4CH1/2C-style — household use of ethanoic acid

Worked examples (5)

• 1Esterification — equation, conditions, naming the product (5 marks, Paper 2)
• 2Name the ester from a given acid + alcohol (4 marks, Paper 2)
• 3Uses of esters and their properties (3 marks, Paper 2)
• 4Lab preparation of ethyl ethanoate (6 marks, Paper 2)
• 5Hydrolysis of esters (4 marks, Paper 2)

Model answers (5)

• ✓Model answer — 4CH1/2C-style — full lab preparation
• ✓Model answer — 4CH1/2C-style — ester naming
• ✓Model answer — 4CH1/2C-style — ester uses
• ✓Model answer — 4CH1/2C-style — H₂SO₄ in esterification
• ✓Model answer — 4CH1/2C-style — saponification + soap

Worked examples (5)

• 1Define key polymer terms and show with poly(ethene) (4 marks, Paper 1)
• 2PVC from chloroethene — equation and uses (4 marks, Paper 1)
• 3Identify the monomer from the repeat unit (3 marks, Paper 1)
• 4Condensation polymerisation — polyester (5 marks, Paper 2)
• 5Compare addition vs condensation polymerisation (5 marks, Paper 2)

Model answers (5)

• ✓Model answer — 4CH1/1C-style — addition polymerisation
• ✓Model answer — 4CH1/2C-style — condensation polymerisation
• ✓Model answer — 4CH1/1C-style — monomer identification
• ✓Model answer — 4CH1/2C-style — environmental impact
• ✓Model answer — 4CH1/1C-style — poly(propene)