Organic Chemistry, complete assessment covering nomenclature, hydrocarbons, alcohols, carbonyls, carboxylic acids, esters, amines, reaction pathways, soaps and polymers from L01-L23. 15 MC questions (auto-marked) + 5 written questions (self-marked). Complete all questions before submitting.
In IUPAC naming, the parent chain is chosen primarily as the:
Which functional group identifies a carboxylic acid?
Alkenes are unsaturated because they contain:
Addition polymerisation of ethene forms:
Complete combustion of an alcohol or hydrocarbon produces:
Hydration of an alkene produces:
Alkanes typically undergo substitution with halogens because they:
Alcohols have relatively high boiling points for their molar mass because they can:
Fermentation produces ethanol from glucose using enzymes and:
A primary alcohol can be oxidised first to:
Tollens reagent gives a positive silver mirror test with:
Esterification commonly reacts a carboxylic acid with:
Soap molecules clean grease because they have:
A reaction pathway question is best solved by:
Condensation polymerisation differs from addition polymerisation because it:
Name the key structural difference between alkanes, alkenes and alkynes, then explain how that difference affects saturation and reactivity.
Alkanes contain only C-C single bonds and are saturated because they have the maximum number of hydrogen atoms for an open-chain hydrocarbon. Alkenes contain at least one C=C double bond and alkynes contain at least one carbon-carbon triple bond, so both are unsaturated. The pi bonds in double and triple bonds are more reactive than sigma bonds, so alkenes and alkynes commonly undergo addition reactions. Alkanes are less reactive and more commonly undergo substitution or combustion.
Marks: 1, alkanes single/saturated | 1, alkenes double/unsaturated | 1, alkynes triple/unsaturated | 1, pi bond/reactivity | 1, addition vs substitution/combustionCompare hydration, substitution and fermentation as routes to alcohols, including one key condition or limitation for each.
Hydration produces alcohols by adding water across an alkene double bond, usually using steam and an acid catalyst in an industrial equilibrium process. Substitution can produce alcohols when a haloalkane reacts with hydroxide ions, replacing the halogen with -OH. Fermentation converts glucose to ethanol using yeast enzymes under anaerobic conditions at moderate temperatures. Fermentation is renewable but slow and produces dilute ethanol, while hydration is faster but uses alkene feedstock from petrochemicals.
Marks: 1, hydration route | 1, hydration condition/context | 1, substitution route | 1, fermentation route/conditions | 1, limitation or comparisonExplain how aldehydes, ketones, carboxylic acids, esters, amines and amides can be distinguished by functional group properties or reactions.
Aldehydes can be distinguished from ketones because aldehydes are readily oxidised and give positive Tollens or Fehling tests, while ketones usually do not. Carboxylic acids are acidic, react with carbonates to release CO2 and form salts with bases. Esters often have distinctive odours and can be hydrolysed to alcohols and carboxylic acids. Amines are basic because the nitrogen lone pair can accept a proton. Amides are much less basic because the nitrogen lone pair is delocalised into the carbonyl group.
Marks: 1, aldehyde/ketone distinction | 1, carboxylic acid reactions | 1, ester property/reaction | 1, amine basicity | 1, amide reduced basicityDesign a pathway from ethene to ethyl ethanoate, then link saponification to soap cleaning action.
Ethene can be hydrated with steam and an acid catalyst to form ethanol. Some ethanol can be oxidised to ethanoic acid using an oxidising agent under suitable conditions. Ethanol and ethanoic acid then react in acid-catalysed esterification to form ethyl ethanoate and water. Saponification is base hydrolysis of fats or oils to produce glycerol and fatty acid carboxylate salts. Soap cleans because each ion has a non-polar hydrocarbon tail that dissolves in grease and an ionic head that interacts with water, allowing grease to be dispersed in micelles.
Marks: 1, ethene to ethanol | 1, ethanol to ethanoic acid | 1, esterification product | 1, saponification products | 1, soap structure and cleaning actionCompare addition and condensation polymers, then explain one environmental issue linked to polymer use.
Addition polymers form when unsaturated monomers such as alkenes open their double bonds and join without eliminating a small molecule. Poly(ethene) is a typical example. Condensation polymers form when bifunctional monomers react at both ends to make links such as ester or amide bonds, releasing a small molecule such as water. Polyesters and polyamides are examples. Environmental issues include persistence in landfill, microplastic formation and harm to ecosystems. Better design, reuse, recycling and biodegradable polymers can reduce but not eliminate these impacts.
Marks: 1, addition polymer definition | 1, addition example | 1, condensation polymer definition | 1, condensation example/byproduct | 1, environmental issue and mitigation