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SingaporeChemistry

Organic Chemistry

10 dot points across 10 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

Why are alkanes relatively unreactive, and how does free-radical substitution proceed?

Describe the bonding and relative inertness of alkanes, their combustion, and the free-radical substitution of alkanes by halogens, including the initiation, propagation and termination steps of the mechanism
A focused answer to the H2 Chemistry learning outcome on alkanes. Their non-polar bonding and inertness, complete and incomplete combustion, and the free-radical substitution mechanism with halogens detailing the initiation, propagation and termination steps.
9 min answer →

Why are alkenes reactive, and how does electrophilic addition explain their reactions and product distribution?

Describe the reactions of alkenes including electrophilic addition of hydrogen halides, halogens and water, oxidation, and the mechanism of electrophilic addition including Markovnikov's rule and carbocation stability
A focused answer to the H2 Chemistry learning outcome on alkenes. The reactive C=C pi bond, electrophilic addition of hydrogen halides, halogens and water, oxidation reactions, and the electrophilic addition mechanism with Markovnikov's rule explained by carbocation stability.
11 min answer →

How does the delocalised structure of benzene explain its stability and its characteristic reactions?

Describe the delocalised structure of benzene and the evidence for it, explain why benzene undergoes electrophilic substitution rather than addition, and describe the mechanisms of nitration and halogenation
A focused answer to the H2 Chemistry learning outcome on arenes. The delocalised ring structure of benzene and the thermochemical evidence for it, why benzene undergoes electrophilic substitution rather than addition, and the mechanisms of nitration and halogenation.
10 min answer →

How do aldehydes and ketones react, and how can they be distinguished from each other?

Describe the reactions of aldehydes and ketones including nucleophilic addition of HCN, reduction, and the use of 2,4-DNPH, Tollens, Fehling and the tri-iodomethane test to identify and distinguish carbonyl compounds
A focused answer to the H2 Chemistry learning outcome on carbonyl compounds. The polar C=O group, nucleophilic addition of HCN, reduction to alcohols, and the tests (2,4-DNPH, Tollens, Fehling, tri-iodomethane) used to detect a carbonyl and distinguish aldehydes from ketones.
10 min answer →

How do carboxylic acids and their derivatives react, and how does structure control their acidity and hydrolysis?

Describe the acidity and reactions of carboxylic acids, the formation and hydrolysis of esters, acyl chlorides and amides, and explain the relative acid strengths of carboxylic acids in terms of inductive effects
A focused answer to the H2 Chemistry learning outcome on carboxylic acids and their derivatives. Acidity and reactions of carboxylic acids, the formation and hydrolysis of esters, acyl chlorides and amides, and how electron-withdrawing groups raise acid strength through the inductive effect.
10 min answer →

How do halogenoalkanes react with nucleophiles, and what controls whether the mechanism is SN1 or SN2?

Describe the nucleophilic substitution and elimination reactions of halogenoalkanes, distinguish the SN1 and SN2 mechanisms, relate the mechanism to the class of halogenoalkane, and explain the relative rates of hydrolysis of the halogenoalkanes
A focused answer to the H2 Chemistry learning outcome on halogenoalkanes. Nucleophilic substitution and elimination reactions, the SN1 versus SN2 mechanisms and how they relate to primary, secondary and tertiary halogenoalkanes, and the trend in hydrolysis rates with bond strength.
11 min answer →

How do alcohols and phenols react, and why is phenol more acidic and more reactive toward the ring than benzene?

Describe the reactions of alcohols including oxidation, esterification, dehydration and the tri-iodomethane test, classify primary, secondary and tertiary alcohols, and explain the greater acidity of phenol and its ease of ring substitution
A focused answer to the H2 Chemistry learning outcome on hydroxy compounds. Classifying alcohols, their oxidation, esterification and dehydration, the tri-iodomethane (iodoform) test, and why phenol is more acidic than ethanol and more reactive than benzene toward electrophilic substitution.
11 min answer →

How are organic molecules named and represented, and what types of isomerism arise from their structure?

Apply IUPAC nomenclature, interpret structural, displayed and skeletal formulae, and describe and identify constitutional (structural) isomerism and stereoisomerism (cis-trans and optical isomerism)
A focused answer to the H2 Chemistry learning outcome on organic structure and isomerism. IUPAC naming, structural, displayed and skeletal formulae, the types of structural isomerism, and stereoisomerism including cis-trans and optical isomerism with chirality.
10 min answer →

How do amines, amides and amino acids behave, and what controls the basicity of an amine?

Describe the preparation and basicity of amines and explain the relative basicity of aliphatic and aromatic amines, describe the hydrolysis of amides, and describe the zwitterion behaviour and isoelectric point of amino acids
A focused answer to the H2 Chemistry learning outcome on organic nitrogen compounds. The preparation and basicity of amines, why phenylamine is a weaker base than ethylamine, the hydrolysis of amides, and the zwitterion and isoelectric point behaviour of amino acids.
10 min answer →

How do addition and condensation polymers form, and how do their structures relate to their properties and disposal?

Distinguish addition and condensation polymerisation, identify the repeat unit and monomers of a given polymer, describe polyesters and polyamides, and discuss the disposal and environmental impact of plastics
A focused answer to the H2 Chemistry learning outcome on polymers. Distinguishing addition from condensation polymerisation, identifying repeat units and monomers, the structure of polyesters and polyamides, and the disposal and environmental impact of plastics.
9 min answer →