Extraction of metals and corrosionIB MYP Chemistry: Mind map

Exam questions on Extraction of metals and corrosion

1. A steelworks in Jamshedpur, India, makes iron in a blast furnace. The furnace is charged with iron ore (mainly haematite, iron(III) oxide, Fe₂O₃), coke (carbon), limestone and hot air.
   Write a balanced symbol equation for the reduction of iron(III) oxide by carbon monoxide.2 marks
2. A student set up three test tubes, each containing a clean iron nail, and left them for one week. Tube 1: the nail was in water that had been boiled to remove dissolved air, with a layer of oil poured on top. Tube 2: the nail was in a stoppered tube with a drying agent (anhydrous calcium chloride) at the bottom, so the air was dry. Tube 3: the nail was half-covered with ordinary tap water and left open to the air. Only the nail in Tube 3 had rusted.
   Identify the independent variable and the dependent variable in this investigation.2 marks
3. At a smelter in Iceland, aluminium is extracted from bauxite, which is purified to give aluminium oxide, Al₂O₃. Iceland's geothermal power stations provide cheap electricity. The aluminium oxide is mixed with molten cryolite in a large steel tank lined with graphite, and a direct current is passed through the mixture.
   Explain why the aluminium oxide is dissolved in molten cryolite for electrolysis instead of being melted on its own.3 marks