topic 4

• What is oxidation?


  loss of electrons, gain of oxygen
• What is the reactivity series?

  A list of elements ordered by their reactivity. (p, s, cal, m, a, car, z, I, t, lea, h, copper, s, gold)
• What is the general formula for when metals react with water?

  metal + water -> metal hydroxide + hydrogen
• What can you react with less reactive metals with instead of water?

  steam
• What is the general formula for when a less reactive metal reacts with steam?

  less reactive metal + steam -> metal oxide + hydrogen
• What is a redox reaction?

  an oxidation reaction paired with a reduction reaction
• What is a displacement reaction?

  A reaction in which a more reactive element takes the place of a less reactive element in a compound

  It is a redox reaction
• What is a metal ore?

  A rock which contains enough metal to make it economically worthwhile extracting the metal from it
• How can carbon be used to extract metal from an ore?

  The ore is reduced using carbon, and the carbon replaces the metal to react with the ore.
• If iron oxide reacted with carbon, what would be the products?

  Iron and carbon dioxide
• Why can't carbon be used to extract aluminium using displacement?

  Because carbon is below aluminium in the reactivity series, so would not displace aluminium.
• What is a disadvantage of using electrolysis to extract metals?

  It is expensive due to the energy needed, for the actual electrolysis as well as melting or dissolving the metal ore so it can conduct electricity.
• What is bioleaching?

  bacteria absorb metal ions and then produce solutions called leachates which contain metal compounds

  these metal ions can be extracted from the leachate, for example using displacement or electrolysis
• What is phytoextraction?

  Growing plants in soil with metal compounds, to be extracted from the plant later

  The plants are dried, harvested and burned.

  The ash contains metal compound which can be extracted by electrolysis or displacement reactions
• Why does recycling conserve resources and energy?

  - can conserve the resources we already have by repurposing them

  - it saves energy as it only uses a fraction of the energy required to extract and refine the metal from scratch

  - metals are a finite resource, and it is very important to recycle materials which are rare
• What are the economic benefits of recycling?

  - uses less energy than extracting new materials so it costs less

  - it is a massive industry and so creates many jobs, whih give people disposable income to contribute to the economy more
• Why does recycling help protect the environment?

  Mines are damaging to habitats, but recycling reduces the need for mining

  It also cuts down on the amount of rubbish that goes into landfill
• What is a life cycle assessment?

  The investigation and valuation of the environmental impacts of a given product or service caused or necessitated by its existence.
• What are the stages of a life cycle assessment?

  choice of material, manufacture, product use, disposal
• What is a reversible reaction?

  a reaction where the products can react together to form the original reactants
• What is dynamic equilibrium?

  Equilibrium in a closed system where the reactions occur at exactly the same rate in each direction
• What three things can change the equilibrium?

  Temperature, concentration, and pressure
• If pressure increases, what happens to equilibrium?

  It moves towards the side with the least gas moles
• If temperature increases, what happens to equilibrium?

  It will favour the endothermic reaction
• If concentration of the products increases, what happens to equilibrium?

  It will move towards the reactants