chp 10 - reversible reactions

    avatar
    Created by
    esther slade

    Cards (9)

    • reversible reaction

      products of the reactions can react to make the original reactants
    • in a closed system the rate of the forward and reverse reactions are equal at equilibrium
    • changing concentration
      if concentration of products builds up - the rate at which they react to reform reactants increase
      this means that the rate of the forward reaction decreases
      because the concentration of the reactants is decreasing from its original maximum value
    • if the forward reaction produces more molecules of gas...
      ... an increase in pressure decreases the amount of products formed
      ... a decrease in pressure increases the amount of products formed
    • if the forward reaction produces fewer molecules of gas ...
      ... an increase in pressure increases the amount of products formed
      ... a decrease in pressure decreases the amount of products formed
    • if the forward reaction is exothermic ...
      ... an increase in temperature decreases the amount of products formed
      ... a decrease in temperature increases the amount of products formed
    • if the forward reaction is endothermic ...
      ... an increase in temperature increases the amount of products formed
      .. a decrease in temperature decreases the amount of products formed
    • Haber Process
      turning nitrogen into ammonia - used for fertilisers
      raw materials used are:
      • nitrogen from the air
      • hydrogen from methane
      the process:
      • a gas stream contains hydrogen and nitrogen
      • the nitrogen / hydrogen mixture is compressed to a pressure of 200 atm and heated to 450 ºC
      • reaction vessel contains the iron catalyst to speed up reaction
      • the mixture of gases emerging from the reactor is cooled, ammonia liquefies in the cooling chamber
      • unreacted nitrogen and hydrogen are returned to the reaction vessel via the compressor
    • contact process
      makes sulfuric acid - used for paints, pigments, fertilisers, plastics, synthetic fibres, dydes
      raw materials:
      • sulfur
      • air
      • water
      stage 1:
      sulfur is burnt and oxidised to sulfur dioxide gas
      stage 2:
      sulfur dioxide is oxidised to make sulfur trioxide in a reversible reaction that takes place at 450 ºC and atmospheric pressure, in the presence of a vanadium oxide catalyst
      stage 3:
      in effect sulfur trioxide reacts with water to make sulfuric acid
    See similar decks