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neurologyYou need to know

• A finite resource is used faster than it is formed, whereas a renewable resource is replaced at a similar or faster rate than it is used.
• Metal ores are finite resources because they form over geological timescales and economically useful deposits can become depleted.
• Reusing a material means using it again without major reprocessing, whereas recycling means processing waste material to make a new product.
• Recycling metals reduces the need to mine ores, reduces waste sent to landfill, and usually uses less energy than extracting metals from ores.
• Copper can be extracted from high-grade copper ores by heating copper compounds with carbon, where carbon reduces the copper compound to copper metal.
• Bioleaching uses bacteria to produce solutions containing copper ions from low-grade copper ores.
• Phytomining uses plants to absorb copper compounds from low-grade ores; the plants are burned and copper is extracted from the ash.
• A life cycle assessment compares the environmental impact of a product over its whole life, including raw material extraction, manufacture, use, transport, and disposal.
• Life cycle assessments are completed to identify environmental impacts such as energy use, water use, pollution, carbon emissions, and waste production.
• Life cycle assessments can be difficult to compare because some data may be missing, uncertain, biased, or given different importance.
• Pure water contains only water molecules, whereas potable water is safe to drink but contains small amounts of dissolved substances.
• Fresh water from groundwater or reservoirs is made potable by filtration to remove solids and sterilisation to kill microbes, usually using chlorine, ozone, or ultraviolet light.
• Desalination removes dissolved salts from sea water by simple distillation or reverse osmosis, but both methods require large amounts of energy.
• Simple distillation separates water from dissolved substances because water evaporates and then condenses, leaving most dissolved solids behind.
• Waste water is made safer by screening to remove large objects, sedimentation to separate sewage sludge from effluent, and aerobic biological treatment to break down organic matter in the effluent.
• Sewage sludge can be treated by anaerobic digestion, which produces biogas that can be used as a fuel.
• An alloy is harder than a pure metal because different-sized atoms distort the layers in the metal structure, making it harder for the layers to slide over each other.
• Steel is an alloy of iron containing carbon, and it is harder than pure iron.
• Iron corrodes when it reacts with oxygen and water to form hydrated iron(III) oxide, which is commonly called rust.
• The Haber process makes ammonia from nitrogen and hydrogen using the reversible reaction, with typical conditions of about 450 °C, 200 atmospheres, and an iron catalyst.

• Extract and interpret data from graphs, charts, and tables by identifying variables, reading values accurately, describing trends, and using evidence to support conclusions.
• Evaluate methods for reducing the use of limited metal ores by comparing reuse, recycling, phytomining, bioleaching, and traditional extraction in terms of energy use, cost, yield, pollution, and resource conservation.
• Use life cycle assessment data to evaluate a material by comparing impacts at each stage and making a justified judgement about the best option for a stated purpose.
• Compare water purification methods by matching each method to the type of impurity removed and weighing up effectiveness, energy demand, cost, and scale of use.
• Carry out simple distillation safely by heating the water sample, condensing the vapour, collecting the distillate, and checking purity using boiling point or absence of dissolved residue.
• Describe the stages of sewage treatment in order, explaining what is removed during screening, sedimentation, aerobic treatment, and anaerobic digestion.
• Explain corrosion prevention by linking barriers, oiling, painting, galvanising, and sacrificial protection to the need to stop iron contacting water and oxygen.
• Write and balance the symbol equation for ammonia production`.
• Explain the Haber process conditions as compromises, linking temperature, pressure, catalyst, rate of reaction, equilibrium yield, cost, and safety.
• Compare fertiliser production in the laboratory and in industry, including batch versus continuous processes, scale, control of reaction conditions, safety, purity, and economic efficiency.