Topic 4

• A method of metal extraction which uses bacteria to extract metals from their ores. The bacteria breaks down low-grade ores to produce an acidic solution containing their metal ions.

  Bacterial extraction
• A reversible reaction will reach this when the forward reaction is equal to the rate of the backward reaction, the concentration of reactants and products remain constant.

  Dynamic equilibrium
• An industrial process which produces ammonia from the reaction between nitrogen and hydrogen. The reaction conditions are 450C and 200 atm and it requires an iron catalyst.

  Haber process
• The analysis of the impact a product has on the environment. It considers the raw materials, manufacturing, packaging, transportation, product use and disposal.

  Life-cycle assessment
• A type of rock which contains metal compounds. The metal or metal compounds are present in sufficient amounts to make it worth extracting them.

  Ore
• A method of metal extraction which uses plants to absorb the metal compounds through their roots. The plants are then burned so that the metal compound can be removed from the ash.

  Phytoextraction
• A reaction in which both oxidation and reduction occur simultaneously.

  Redox reaction
• Process used to extract metals from their oxides when the metal is less reactive than carbon. The metal oxide is heated with carbon so that carbon reduces the metal oxide to the metallic element.

  Reduction with carbon
• A reaction in which the products can react together to reform the reactants.

  Reversible reaction