Chemistry 9701 · AS & A Level · Hydrocarbons

Hydrocarbons — practice question

Naphtha is a mixture made up only of hydrocarbon molecules.
(a(i))[1]

What is meant by hydrocarbon?

(a(ii))[1]

Name the starting material used to make a sample of naphtha.

(b(i))[1]

Compound $V$ is present in naphtha and has molecular formula $\text{C}_{10}\text{H}_{22}$. When $V$ is heated under high pressure and without air, equal moles of ethene, propene and $W$ are formed. $W$ is a straight-chain saturated compound. Name the process for this reaction.

(b(ii))[1]

Use the information to deduce the structure of $W$. Draw its structure below.

(c(i))[1]

Propene is removed from the mixture and heated in air with a catalyst present. Propene is then oxidised to $X$, and $X$ contains two functional groups. When $\text{Na}_2\text{CO}_3(aq)$ is added to $X$, fizzing is observed. Identify the functional group in $X$ responsible for this observation.

(c(ii))[2]

Identify a reagent that could be used to show that $X$ contains a $\text{C}=\text{C}$. Include the relevant observations.

(d)[1]

$X$ reacts with another reagent to make $Y$. Molecules of $Y$ then join together to form the addition polymer $Z$. The diagram gives the repeat unit of polymer $Z$. Draw the structural formula of monomer $Y$.

(e(i))[1]

$Z$ is useful because it can absorb large amounts of water. However, disposing of products that contain $Z$ causes problems. Burning pure $Z$ is not suitable because this process gives off harmful gases, some of which contribute to the enhanced greenhouse effect. Identify a gas released when $Z$ burns that contributes to the enhanced greenhouse effect.

(e(ii))[1]

Identify one other gas that could be formed when pure $Z$ is burnt. Describe one consequence, other than the enhanced greenhouse effect, of its release into the atmosphere.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: Compounds or molecules that contain only carbon and hydrogen atoms

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI