This reaction is used at a plastics factory to make ethene from a heavier hydrocarbon fraction. Fig. 1 shows a laboratory model of the cracking apparatus. P...

This reaction is used at a plastics factory to make ethene from a heavier hydrocarbon fraction. Fig. 1 shows a laboratory model of the cracking apparatus. Paraffin oil is soaked into mineral wool and heated. The vapour passes over hot aluminium oxide catalyst, then the products are collected over water. A student adds bromine water to a sample of the collected gas. The orange colour disappears. The student must not heat the delivery tube after removing the flame because water could be drawn back into hot glass.

(a) Give the name of the reaction occurring over aluminium oxide. [1]
(b) Describe the bromine water result that shows an alkene is present. [1]
(c) How does ethene differ in bonding from the alkane used at the start? [2]

Fig. 1 shows two structural formulae drawn by a student during a lesson on isomers. Both compounds have the molecular formula C4H10. The student has placed a box around the part of compound Y where the carbon chain branches. The two liquids have different boiling points, even though each molecule contains four carbon atoms and ten hydrogen atoms. This is because the atoms are connected in a different arrangement. The student is asked to use correct names rather than calling both samples butane.

(a) Give the name used for compounds with the same molecular formula but different structures. [1]
(b) Use Fig. 1 to state the name of compound X. [1]
(c) Describe one structural difference between X and Y. [2]