Chemistry 5070 · O Level · Alkanes

Alkanes — practice question

The alkanes form a homologous series made up of saturated hydrocarbons.
(a(i))[1]

Write the general formula for the homologous series of alkanes.

(a(ii))[1]

Give one further characteristic of a homologous series.

(b)[1]

What does the term saturated mean?

(c)[2]

Construct the equation for the complete combustion of pentane, $\text{C}_5\text{H}_{12}$.

(d)[1]

Draw the structure of a branched alkane with formula $\text{C}_5\text{H}_{12}$. Include all atoms and every bond.

(e(i))[1]

Chlorine reacts with pentane. $\text{C}_5\text{H}_{12}+\text{Cl}_2\rightarrow \text{C}_5\text{H}_{11}\text{Cl}+\text{HCl}$. What name is given to this type of chemical reaction?

(e(ii))[1]

What essential condition has to be present for chlorine to react with pentane?

(f(i))[2]

A hydrocarbon has a carbon mass percentage of 90%. Deduce the empirical formula of this hydrocarbon.

(f(ii))[1]

What additional piece of information is needed to deduce the molecular formula of this hydrocarbon?

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: CₙH₂ₙ₊₂

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