GCSE Chemistry: Haber Process, Fertilisers and Materials

The last topic of GCSE Chemistry, using resources, is about how chemistry supplies what people need: food, through fertilisers made from ammonia; long-lasting metal structures, through alloys and corrosion protection; and a whole range of materials, from glass and clay ceramics to polymers and composites. The category's using resources material already covers drinking water, sewage treatment, life cycle assessments and recycling; this material covers the remaining content, most of which is chemistry-only.

The quiz opens with the Haber process: the iron catalyst, the temperature of about 450 °C and the pressure of about 200 atmospheres, and what happens after the reactor — ammonia is removed as a liquid on cooling, and the unreacted nitrogen and hydrogen are recycled. The effect of these conditions on the equilibrium is practised in the category's equilibrium material, so here the focus is on the process itself. Fertiliser questions ask how ammonium nitrate is made and what happens when insoluble phosphate rock is treated with sulfuric acid.

The materials questions follow. You interpret a three-tube experiment to decide which iron nail rusts, explain how a more reactive metal gives sacrificial protection, calculate the mass of pure gold in an 18 carat ring, choose a strong, low-density alloy for aircraft, compare soda-lime and borosilicate glass, explain why thermosetting polymers do not melt, and recognise composites. A Higher-tier question asks how copper is obtained by phytomining and how that differs from bioleaching — the biological methods used for low-grade copper ores.

The flashcards collect the facts to learn by heart: the Haber equation and conditions, the NPK elements, the compositions of bronze, brass and stainless steel, what 18 carat means, what rusting needs, and definitions of thermosetting and thermosoftening polymers, composites, phytomining and bioleaching. In the oral exam an examiner asks one question at a time across the topic and gives brief, precise feedback at the end. The printable written work contains eight longer tasks answered by hand: describing the Haber process, making fertilisers, carat calculations, comparing steels, explaining corrosion protection when a coating is scratched, choosing ceramics and composites, explaining polymer properties from their structure and, at Higher tier, evaluating phytomining and bioleaching. Each task is checked against a model answer.

The content is based on the using resources section of the DfE GCSE chemistry subject content; for example, AQA places using materials and the Haber process and NPK fertilisers in the chemistry-only content, and the biological methods of metal extraction in the Higher-tier content.

• Describe the Haber process: raw materials, conditions, catalyst and the recycling of unreacted gases
• Describe how NPK fertilisers are made from ammonia, phosphate rock and potassium salts
• Describe the conditions for rusting and explain barrier and sacrificial protection
• Recall the composition and uses of common alloys and calculate gold content from carats
• Compare soda-lime and borosilicate glass, clay ceramics and composites
• Explain the properties of thermosoftening and thermosetting polymers from their structure
• Describe phytomining and bioleaching and how copper is extracted from their products (Higher tier)

Practice material written by Zestly, based on the DfE GCSE chemistry subject content (using resources: alternative methods of extracting metals, using materials, the Haber process and NPK fertilisers); chemistry-only and Higher-tier placement given as an example from the AQA GCSE Chemistry (8462) specification.