Question 1: Define 'reduction' in the context of metal extraction.

Answer: Reduction is the chemical process of gaining electrons, often used to describe the removal of oxygen from a compound during metal extraction.

Question 2: Explain why aluminium is extracted using electrolysis rather than reduction with carbon.

Answer: Aluminium is extracted from bauxite using electrolysis because it is too reactive to be reduced by carbon, which cannot provide enough electrons to reduce aluminium ions.

Question 3: What is the main difference between smelting and electrolytic extraction?

Answer: Smelting involves heating and reducing ores with carbon, while electrolytic extraction uses electric current to obtain pure metals from their compounds.

Question 1: Calculate the amount of electrical charge (in coulombs) required to extract 10 grams of aluminium from aluminium oxide (Al₂O₃) via electrolysis. (Molar mass of Al = 27 g/mol, 3 moles of electrons are needed per mole of Al).

Answer: Charge = (Number of moles of Al) × (Number of electrons per mole) × (Faraday's constant). Number of moles of Al = 10 / 27 ≈ 0.370 mol. Total electrons = 0.370 × 3 ≈ 1.11 mol. Charge = 1.11 mol × 96485 C/mol ≈ 107,109 C.

Question 1: Describe a basic experiment to extract copper from its ore using smelting. Include the main variables you would control.

Answer: The experiment involves heating copper ore (e.g., copper carbonate) in a furnace with a reducing agent like coke. Main variables to control include temperature, amount of coke, and airflow. The heat causes the copper carbonate to decompose, and the carbon reduces copper oxide to copper metal. Safety precautions include ensuring proper ventilation and protective equipment.

Question 1: A sample of ore was subjected to electrolysis, and 0.5 mol of electrons were transferred. If the ore contains zinc ions (Zn²⁺), estimate the mass of zinc metal produced. (Atomic mass of Zn = 65 g/mol).

Answer: Zinc ions gain 2 electrons per atom. Moles of zinc produced = 0.5 mol e⁻ / 2 = 0.25 mol. Mass of zinc = 0.25 mol × 65 g/mol = 16.25 g.

Question 1: Explain why electrolysis is used to extract certain metals such as aluminium, but carbon reduction is used for metals like zinc and iron. Include in your answer the reactivity series and the implications for industrial extraction.

Answer: Electrolysis is used for metals like aluminium because they are too reactive to be reduced by carbon; their positive ions cannot be reduced at lower temperatures with carbon. Metals like zinc and iron are less reactive and can be extracted by reduction with carbon because their ions gain electrons more easily, making the process cost-effective. The reactivity series shows aluminium is higher than carbon, so electrolysis is necessary for its extraction, whereas zinc and iron are below carbon, allowing reduction with coke in smelting.

Question 1: Discuss how the extraction methods of aluminium and zinc impact their use in the construction industry. Include considerations of cost, energy consumption, and environmental impact.

Answer: Aluminium extraction via electrolysis is energy-intensive and costly, but produces a lightweight, corrosion-resistant metal ideal for aircraft and window frames. Zinc, extracted by smelting with carbon, is cheaper and requires less energy, making it suitable for galvanising steel to prevent rust. Environmental impacts differ: electrolysis consumes significant electricity, often from non-renewable sources, contributing to CO₂ emissions, while smelting releases sulphur dioxide, which can cause acid rain. Both methods influence industry choices based on cost, performance, and environmental considerations.