Paper 2: Organic and Physical Chemistry

Name CH₃CH(CH₃)CH₂CH₂OH and CH₃COCH₂CH₃.

Draw or name the three structural isomers of C₅H₁₂.

Methane reacts with chlorine in UV light. Outline the mechanism to form chloromethane, naming each stage.

Outline the mechanism for the reaction of bromoethane with aqueous hydroxide ions.

Give the conditions that favour elimination rather than substitution when a halogenoalkane reacts with hydroxide ions.

Explain why iodoalkanes react faster than chloroalkanes in nucleophilic substitution.

Write two equations to show how chlorine radicals catalyse the decomposition of ozone.

Explain why 2-bromopropane rather than 1-bromopropane is the major product when propene reacts with HBr.

Give a test for an alkene and the result.

Compare the production of ethanol by fermentation and by hydration of ethene.

Describe how propan-1-ol can be oxidised to (a) propanal and (b) propanoic acid.

Name the type of reaction and a catalyst used to convert butan-2-ol into alkenes, and explain why more than one alkene forms.

Compound X, C₄H₈O₂, has an IR absorption at 1740 cm⁻¹ and no broad absorption at 2500–3300 cm⁻¹. Its ¹H NMR spectrum shows:

δ / ppm	Integration	Splitting
4.1	2	quartet
2.0	3	singlet
1.2	3	triplet

Deduce the structure of X, explaining your reasoning.

Complete combustion of 0.440 g of a hydrocarbon produced 1.32 g of CO₂ and 0.72 g of H₂O. Deduce its empirical formula.

Ethanal reacts with HCN (from KCN and acid) to form 2-hydroxypropanenitrile. Outline the mechanism and explain why the product is a racemic mixture.

Describe a test to distinguish propanal from propanone.

Name the product when butanone is reduced by NaBH₄, name the mechanism, and state whether the product is optically active.

Write an equation for the formation of methyl propanoate and name the catalyst.

Explain how vegetable oils are converted to biodiesel and why biodiesel is described as carbon neutral, with one reason why this is not completely true.

Outline the mechanism for the reaction of ethanoyl chloride with methylamine.

Give three reasons why ethanoic anhydride is used rather than ethanoyl chloride to make aspirin industrially.

The enthalpy of hydrogenation of cyclohexene is −120 kJ mol⁻¹. Benzene's is −208 kJ mol⁻¹. Explain what this shows about the bonding in benzene.

Outline the mechanism for the nitration of benzene, including the formation of the electrophile.

Explain the order of base strength: ethylamine > ammonia > phenylamine.

Explain why excess ammonia is used to make ethylamine from bromoethane.

Draw the repeating unit of the polyamide formed from 1,6-diaminohexane and hexanedioic acid.

Explain why polyesters and polyamides are biodegradable but polyalkenes are not.

Draw the species formed by glycine (H₂NCH₂COOH) at pH 1 and at its isoelectric point.

Explain how cisplatin acts as an anticancer drug and give one disadvantage.

Explain why there are two hydrogen bonds between adenine and thymine but three between guanine and cytosine.

Give a two-step synthesis of propanoic acid from 1-bromopropane, with reagents and conditions.

In TLC, a spot travelled 3.6 cm and the solvent 8.0 cm. Calculate Rf and explain how separation occurs.

Explain how gas chromatography can be used to identify the components of a mixture.

Figure 1 shows Maxwell–Boltzmann distributions at two temperatures. Explain why a small rise in temperature leads to a large increase in rate.

50.0 cm³ of 1.00 mol dm⁻³ HCl was mixed with 50.0 cm³ of 1.00 mol dm⁻³ NaOH. The temperature rose by 6.8 K. Calculate the enthalpy of neutralisation (c = 4.18 J g⁻¹ K⁻¹; density 1.00 g cm⁻³).

Explain why the enthalpy of formation of methane cannot be measured directly and how it can be found.

Use mean bond enthalpies to calculate ΔH for C₂H₄ + H₂ → C₂H₆.

Bond	C=C	H–H	C–C	C–H
kJ mol⁻¹	612	436	348	412