Paper 2: Organic and Physical Chemistry

Give the general formula of the alkenes and name the homologous series to which CH₃CH₂CHO belongs.

Explain what is meant by E/Z isomerism, using but-2-ene as an example.

Explain why fractional distillation separates crude oil into fractions.

Explain how the conditions affect whether 2-bromopropane undergoes substitution or elimination with hydroxide ions.

Give the product of the reaction of 1-bromopropane with KCN in ethanol and explain its usefulness in synthesis.

Describe the mechanism of the reaction between ethene and bromine.

Explain why poly(alkenes) are unreactive.

Ethanol can be made by fermentation or by hydration of ethene. Give one advantage of each method.

Describe a chemical test to show that a compound is a primary or secondary alcohol rather than a tertiary alcohol.

Explain how the fingerprint region of an IR spectrum is used to identify a compound.

The mass spectrum of a ketone has a molecular ion peak at m/z 58 and a large peak at m/z 43. Identify the ketone and the ion responsible for the peak at 43.

Draw (describe) the two enantiomers of butan-2-ol and explain how they could be distinguished.

Describe the reduction of propanone with NaBH₄ and name the product.

Describe the hydrolysis of an ester in acidic and in alkaline conditions and explain why alkaline hydrolysis goes to completion.

Explain how biodiesel is made from vegetable oils.

Describe Friedel–Crafts acylation of benzene with ethanoyl chloride, including the role of the catalyst.

Explain why phenylethanone is useful in synthesis.

Explain why reacting bromoethane with ammonia produces a mixture of amines.

Give one use of quaternary ammonium salts.

Describe the reaction of ethylamine with ethanoyl chloride. Name the type of reaction and the organic product.

Explain why nylon-6,6 has a high tensile strength.

Explain how the primary and tertiary structures of a protein differ, and how the tertiary structure is maintained.

Explain how DNA's two strands are held together.

Explain why many drugs are made as a single enantiomer rather than a racemic mixture.

Suggest a synthesis of propanoic acid from 1-bromopropane in two steps, giving reagents and conditions.

How many peaks are in the ¹³C NMR spectrum of butanone, CH₃COCH₂CH₃? Explain.

A compound C₃H₈O has a ¹H NMR spectrum with a doublet (6H), a septet (1H) and a singlet (1H). Identify it.

Explain why amino acids in a mixture can be separated by thin-layer chromatography.

The decomposition of N₂O₅ is first order. Its concentration fell from 0.0800 to 0.0400 mol dm⁻³ in 690 s (data are illustrative, written for this paper). Calculate the half-life and the rate constant.

Calculate the pH of 0.0250 mol dm⁻³ Ba(OH)₂ at 298 K.

1.20 mol of a gas is heated to 573 K in a 0.0566 m³ container. Calculate the pressure in kPa.

Calculate ΔH for C₂H₄(g) + H₂O(g) → C₂H₅OH(g) using enthalpies of formation (kJ mol⁻¹): C₂H₄ +52, H₂O(g) −242, C₂H₅OH(g) −235.

Use your answer to 15.4 to explain the effect of increasing temperature and pressure on the equilibrium yield of ethanol.

A student makes aspirin from 2-hydroxybenzoic acid and ethanoic anhydride. Describe how the crude product is purified by recrystallisation and how its purity and identity can be checked.

Compare the mechanisms of the reaction of propene with hydrogen bromide and of propanal with hydrogen cyanide. Explain why the attacking species differs.