OCR A Level Chemistry A Synthesis and analytical techniques November 2020 question paper H432/02

What is the name of the compound below?

H₃C CH₂CH₃

A E-3-bromopent-2-ene

B E-3-bromopent-3-ene

C Z-3-bromopent-2-ene

D Z-3-bromopent-3-ene

Which statement about bonds is correct?

A The C=C bond in ethene is more polar than the C−C bond in ethane.

B A -bond is stronger than a -bond.

C The H−C−H bond angle in ethane is greater than the H−C−H bond angle in ethene.

D A -bond is formed from sideways overlap of p orbitals.

Which of these reagent(s) will not react with HOCH₂CH₂CH₂COOH?

A NaCN in ethanol

B C₂H₅OH in the presence of an acid catalyst

C (CH₃CO)₂O

D concentrated H₂SO₄

Which compound can be refluxed with acidified potassium dichromate(VI) to form an organic product with molecular formula C₅H₈O₂?

Which structure shows a section of poly(propene)?

Which alcohol reacts with an acid catalyst to form a mixture of stereoisomers?

A 3-methylbutan-2-ol

B pentan-1-ol

C 2-methylhexan-2-ol

D heptan-4-ol

Which one of the following reacts with ethanoic acid and with phenol?

A Aqueous potassium hydroxide

B Bromine

C Calcium carbonate

D Methanol and an acid catalyst

Which isomer of C₆H₁₂O₂ produces the smallest number of peaks in its¹³C NMR spectrum?

What is the structural formula of ethyl 3-methylbutanoate?

A CH₃CH₂COOCH₂CH₂CH(CH₃)₂

B CH₃CH₂COOCH(CH₃)CH₂CH₃

C CH₃CH₂CH(CH₃)COOCH₂CH₃

D (CH₃)₂CHCH₂COOCH₂CH₃

What is the number of alicyclic structural isomers of C₅H₁₀?

A 3

B 4

C 5

D 6

Complete combustion of 1.00 g of a hydrocarbon gives 3.38 g carbon dioxide.

What is the empirical formula of the hydrocarbon?

A CH

B CH₂

C C₂H₅

D C₃H₈

What is the molecular formula of the steroid molecule below?

Which statement(s) is/are correct for gas chromatography?

1 The components in a mixture can be identified from their retention time.

2 The relative peak areas give the proportions of components in a mixture.

3 Calibration curves are used to confirm the concentrations of components in a mixture.

A 1, 2 and 3

B Only 1 and 2

C Only 2 and 3

D Only 1

Which of the following reactions produce propan-1-ol?

1 The alkaline hydrolysis of 1-chloropropane.

2 The acid hydrolysis of propyl methanoate.

3 The acid hydrolysis of propanenitrile.

A 1, 2 and 3

B Only 1 and 2

C Only 2 and 3

D Only 1

Which compound(s) could be prepared by reacting benzene with an acyl chloride in the presence of a halogen carrier?

A 1, 2 and 3

B Only 1 and 2

C Only 2 and 3

D Only 1

Hydrocarbon A can be reacted with bromine in the presence of ultraviolet radiation to prepare (CH₃)₃CCHBrCH₃.

What is the systematic name for (CH₃)₃CCHBrCH₃?

(CH₃)₃CCHBrCH₃has stereoisomers.

Explain the term stereoisomers and name this type of stereoisomerism.

Explanation:........

Type of stereoisomerism:........

Draw 3D diagrams for the stereoisomers of (CH₃)₃CCHBrCH₃.

Complete the table to show the mechanism for the reaction of hydrocarbon A with Br₂ to form (CH₃)₃CCHBrCH₃.

Use skeletal formulae for all organic compounds. Use ‘dots’ (●) to show the position of unpaired electrons.

State two limitations of using radical substitution in organic synthesis.

Compounds B and C, shown below, are unsaturated hydrocarbons containing nine carbon atoms.

Compound B reacts with chlorine at room temperature, but compound C requires the presence of a halogen carrier.

In both reactions, the organic compound reacts with chlorine in a 1:1 molar ratio.

Draw the structures of the organic product of each reaction.

Outline the mechanism for the reaction of compound C with chlorine.

Show the role of the halogen carrier.

Compound C can be prepared by ‘trimerisation’ of propanone using concentrated sulfuric acid as a catalyst.

Suggest an equation for this reaction, using molecular formulae.

An organic chemist is investigating compound D for possible use as a medicine.

The chemist proposes a synthesis of compound D from compound C.

The chemist develops a three-stage synthesis of compound D from compound C.

Complete the flowchart. Show structures for organic compounds.

Alcohols can be used to prepare organic compounds with different functional groups.

HO(CH₂)₄OH can be oxidised to form HOOC(CH₂)₂COOH.

State the reagents and conditions and write an equation for this oxidation.

In the equation, use [O] for the oxidising agent.

Reagents and conditions:........

Equation:

HOOC(CH₂)₂COOH is soluble in water.

Explain, using a labelled diagram, why HOOC(CH₂)₂COOH is soluble in water.

HOOC(CH₂)₂COOH and HO(CH₂)₄OH react together to form polymer E.

Draw one repeat unit of polymer E.

The functional groups should be clearly displayed.

Governments are encouraging the development of biodegradable polymers to reduce dependency on persistent plastic waste derived from fossil fuels.

Polymer E is a biodegradable polymer.

Suggest why polymer E is able to biodegrade.

The carbonyl compounds, F and G, shown below, contribute to the flavour of coffee.

Compound F is a member of a homologous series.

Explain the term homologous series.

Predict the molecular formula for the member of this homologous series containing 24 carbon atoms.

Describe suitable chemical tests, with observations, that would confirm the presence of the functional groups in F and G.

Explain why the mechanism in (c)(i) involves heterolytic fission.

Cyclopentanol can be reacted to form cyclopentene. Cyclopentene is a liquid with a boiling point of 44 °C and a density of 0.74 g cm⁻³.

A student plans to prepare 4.00 g of cyclopentene by reacting cyclopentanol (boiling point 140 °C) with an acid catalyst.

The expected percentage yield of cyclopentene is 64.0%.

Method The student carries out the preparation using apparatus set up for distillation, as shown below.

1 The reaction mixture is heated gently, and a distillate containing impure cyclopentene is collected.

2 The distillate has an aqueous layer and an organic layer. The student purifies the cyclopentene from the distillate.

* Calculate the mass of cyclopentanol that the student should use and explain how pure

cyclopentene could be obtained from the distillate.

This question is about organic compounds containing nitrogen.

Salt H, (CH₃)₂CHNH₃Cl, is used in the manufacture of garden weedkillers.

The flowchart shows the synthesis of the salt H from propanone.

Complete the flowchart. Show structures for organic compounds.

Aspartame, shown below, is an artificial sweetener commonly used as a sugar substitute.

Aspartame contains several functional groups.

Apart from the benzene ring, name the functional groups in aspartame.

A sample of aspartame is hydrolysed with aqueous acid.

Draw the structures of the three organic products of the complete acid hydrolysis aspartame.

An organic compound I is analysed, using a combination of techniques. The analytical data is shown below.

Elemental analysis by mass C, 56.69%; H, 7.09%; N, 11.02%; O, 25.20%

Mass spectrum Molecular ion peak at m / z = 127.0

IR spectrum

Proton NMR spectrum

Explain the use of two deuterated compounds in NMR spectroscopy.

* Determine the structure of compound I, showing all your reasoning.