(a) State the monomer units of (i) polyethene; (ii) cellulose (b) Name the two fuels obtained when steam and air are passed over red-hot coke.

Answer Details

(a) Monomer units:

• (i) Polyethene is formed from the monomer ethene (ethylene), \(CH_2=CH_2\).
• (ii) Cellulose is a natural polymer whose monomer unit is glucose (\(\beta\)-glucose), \(C_6H_{12}O_6\).

(b) When steam and air are passed over red-hot coke, the two fuel gases obtained are:

• Water gas (a mixture of carbon(II) oxide and hydrogen, \(CO + H_2\)), formed by the action of steam on red-hot coke: \[C_{(s)} + H_2O_{(g)} \rightarrow CO_{(g)} + H_{2(g)}\]
• Producer gas (a mixture of carbon(II) oxide and nitrogen, \(CO + N_2\)), formed by the action of air on red-hot coke: \[2C_{(s)} + O_{2(g)} \rightarrow 2CO_{(g)}\] the nitrogen of the air passing through unreacted.