A-Level Chemistry: Condensation Polymers and Organic Synthesis

Two topics close the A-level organic course and pull together much of what came before it: condensation polymers, which reuse the chemistry of esters, amides and acyl chlorides, and organic synthesis, which asks you to chain the reactions of the whole specification into a route from one compound to another. This material practises both.

For polymers, you start by contrasting condensation polymerisation with addition polymerisation: condensation monomers carry two functional groups, and each link formed releases a small molecule such as water or hydrogen chloride. You then meet the named examples: the polyester Terylene, made from benzene-1,4-dicarboxylic acid and ethane-1,2-diol; the polyamide nylon 6,6, made from hexane-1,6-diamine and hexanedioic acid or its diacyl dichloride; and Kevlar, made from benzene-1,4-diamine and benzene-1,4-dicarboxylic acid, whose rigid chains and hydrogen bonds between chains make it strong enough for body armour. You practise the three skills examiners test: writing the repeating unit from the monomers, finding the repeating unit in a section of chain, and working back from a polymer to its monomers. You also explain the intermolecular forces between chains, why polyesters and polyamides can be hydrolysed by acid or alkali and are biodegradable while polyalkenes are inert, and weigh landfill, incineration and recycling as ways of dealing with waste polymers.

For synthesis, you choose reagents and conditions for two- and three-step routes, for example hydration of propene followed by oxidation to propanone, the use of cyanide ions to lengthen a carbon chain followed by reduction of the nitrile to an amine, and nitration of benzene followed by reduction to phenylamine. You also explain why chemists prefer routes with fewer steps, high atom economy, no solvent and non-hazardous starting materials, and calculate an atom economy to compare two routes.

Four formats are offered. The 12-question quiz mixes structure questions (every structure is written as a condensed formula, so no diagram is needed) with reagent-choice questions. The flashcards list the links, the named polymers and their monomers, and the reagents for key synthesis steps. The written work has eight questions to answer by hand, including repeating units, a disposal comparison and full synthesis routes, each with a reference answer. The oral exam asks you to explain polymers and plan routes aloud for an examiner, one question at a time.

The content is based on the A-level chemistry content on condensation polymers, their disposal and organic synthesis, as set out for example in the AQA A-level specification. It is revision practice written by Zestly, not an exam board resource.

• Distinguish condensation from addition polymerisation and name the small molecule eliminated
• Write repeating units of polyesters and polyamides (Terylene, nylon 6,6, Kevlar) from monomers, and identify monomers from a polymer chain
• Explain the intermolecular forces between condensation polymer chains
• Explain why polyesters and polyamides are hydrolysable and biodegradable but polyalkenes are not, and compare disposal methods
• Devise synthesis routes of up to four steps with reagents and conditions
• Explain the aims of fewer steps, high atom economy, no solvent and non-hazardous starting materials

Practice material written by Zestly, based on the A-level chemistry content on polymers and organic synthesis (for example AQA A-level Chemistry 7405, sections 3.3.12 and 3.3.14).