Hydrocarbons

Ethene is bubbled into two separate test-tubes, one containing aqueous hydrogen bromide and the other containing cold, dilute acidified potassium manganate(VII).

In each case, describe any colour changes you would see and give the structural formula of the organic product.

Draw the structural formula of the compound formed when cyclohexene is reacted with bromine.

State as fully as you can what type of reaction this is.

Draw the structural formula of the compound formed when cyclohexene is reacted with hot concentrated acidified potassium manganate(VII).

Give two different conditions under which long chain hydrocarbons may be cracked.

Dodecane, C₁₂H₂₆, is a long chain hydrocarbon which is present in crude oil and which can be cracked to form but-2-ene and an alkane.

Write a balanced equation for this reaction.

Some reactions of but-2-ene are shown below.

In the boxes below, give the structural formulae of the organic compounds A to D.

Suggest the structural formula of the product of the reaction between E and an excess of bromine.

What type of reaction occurs between E and an excess of bromine?

The test-tube in the dark is kept cool and is not exposed to ultraviolet light.

Explain the observations for the test-tube kept in the dark.

State the name of the mechanism of the reaction that occurs.

Give an equation which shows a propagation step in this reaction in which hexane produces $\bullet\text{C}_6\text{H}_{13}$.

Give an equation which shows a propagation step in this reaction that produces 1-bromohexane.

Give an equation which shows a termination step in this reaction that produces 1-bromohexane.

Draw the structural formula of A.

State the conditions needed for this reaction of A.

Name the type of reaction occurring.

Explain these observations.

Draw the skeletal formula of P and give its name.

name of P

There are several structural isomers of P that also decolourise bromine, but only four of these structural isomers exhibit geometrical (cis-trans) isomerism.

Give the structures of any three structural isomers of P that exhibit geometrical (cis-trans) isomerism.

Give the structures for organic compounds Q, R, S and T.

Compound U contains a chiral centre and has the same molecular formula as compound P, $\text{C}_5\text{H}_8\text{O}$.

• Compound U readily decolourises a sample of bromine water.
• Compound U does not show cis-trans isomerism.
• When compound U is heated under reflux in the presence of excess acidified potassium dichromate(VI), the organic product gives the infra-red spectrum shown.

Use the information given to suggest a structure for compound U.
Explain your answer.

With propene, 1,2-dichloropropane, $\text{CH}_3\text{CHClCH}_2\text{Cl}$ is formed.

State fully what type of reaction this is.

When cyclopropane reacts with chlorine, three different compounds with the molecular formula $\text{C}_3\text{H}_4\text{Cl}_2$ can be formed.

Draw displayed structures of each of these three compounds.

With propene, 1,2-dichloropropane, CH₃CHClCH₂Cl is formed.

State fully what type of reaction this is.

When cyclopropane reacts with chlorine, three different compounds with the molecular formula C₃H₄Cl₂ can be formed.

Draw displayed structures of each of these three compounds.

Give the names of one physical process and one chemical process carried out during the processing of crude oil.

physical process

chemical process

Explain why alkanes are unreactive.

Use a series of equations to describe the mechanism of the reaction of ethane with chlorine to form chloroethane. Name the steps in this reaction.

Write an equation to show how butane could be produced as a by-product of this reaction.