A teacher mixes aluminium powder with iodine crystals on a heatproof mat in a fume cupboard. When a drop of water is added, the mixture reacts vigorously and clouds of purple vapour are seen.
2Al(s)+3I2(s)→2AlI3(s)\mathrm{2Al(s)} + \mathrm{3I_{2}(s)} \rightarrow \mathrm{2AlI_{3}(s)}2Al(s)+3I2(s)→2AlI3(s)
Relative atomic masses: Al = 27, I = 127
Suggest why a purple vapour is seen during the reaction.
Calculate the maximum mass of aluminium iodide that can be made from 0.54 g of aluminium when iodine is in excess.
In a second experiment, the teacher uses 0.54 g of aluminium and 6.35 g of iodine.
Determine which reactant is the limiting reactant. You must show your working.
Calculate the maximum mass of aluminium iodide formed in this experiment.
Aluminium iodide contains iodide ions, I−\mathrm{I^{-}}I−. Explain why iodine is described as being reduced in this reaction.
41 exam-style questions on Edexcel GCSE Chemistry 7.2 Group 7, covering 7.2.1 Physical properties of the halogens, 7.2.2 Reactions of the halogens, 7.2.3 Relative reactivity and displacement reactions of the halogens, and 7.2.4 Halogen displacement as a redox reaction. Each one has a worked solution and a mark scheme showing where the marks go.