Tran

View mindmap
  • Catalysis
    • Heterogeneous
      • Catalysts that are in a different phase to the reactants.
        • Increase Efficiency
          • Increase Surface Area
          • Spread into an inert medium to increase the surface to mass ratio so a little goes a long way.
        • Examples
          • The Haber Process
            • N2 + 3 H2  2 NH3
            • Iron catalyst in pea size lumps
              • Lasts five years, then becomes poisoned by impurities in the gas stream such as Sulphur compounds.
          • The Contact Process
            • 2 SO2(g) + O2(g) ? 2 SO3(g)
            • Makes Sulphuric Acid. This is vital in the industry.
            • Vanadium(V) Oxide catalyst
              • SO2 + V2O5 ? SO3 + 2VO2
                • 2VO2 +½O2 ? V2O5
              • There is lower activation energy in both the steps than the un-catalysed reaction. Therefore it goes faster.
                • Good example that variability in oxidation states are useful in Catalysts.
    • Homogeneous
      • When the catalyst is in the same phase as the reactants
        • Oxidation of Iodine ions to Iodine.
          • Fe2+ Catalyst
            • 1) 2Fe2+(aq) + S2O8-(aq) ? 2Fe3+(aq) + 2SO42-(aq)
              • 2) 2Fe3+(aq) + 2I-(aq) ? 2Fe2+(aq) + I2(aq)
            • As both reactants are negative ions the reaction has a high Activation Energy. Therefore using a catalyst requires a lot less energy.
          • S2O82-(aq) + 2I- (aq) ? 2SO42-(aq) + I2(aq)
    • Autocatalysis
      • When one of the products of a reaction becomes a catalyst. This increases the rate rapidly as more of the catalyst is formed.
        • Oxidation of Ethanedioic Acid by Manganate (VII) Ions
          • 2MnO4-(aq) + 16H+(aq) + 5C2O42-(aq)  ?  2Mn2+(aq) + 8H2O(l) + 10CO2(g)

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Transition metals resources »