Tran
- Created by: Nibblepoo14356
- Created on: 27-03-19 10:21
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- 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.
- SO2 + V2O5 ? SO3 + 2VO2
- The Haber Process
- Increase Efficiency
- Catalysts that are in a different phase to the reactants.
- 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.
- 1) 2Fe2+(aq) + S2O8-(aq) ? 2Fe3+(aq) + 2SO42-(aq)
- S2O82-(aq) + 2I- (aq) ? 2SO42-(aq) + I2(aq)
- Fe2+ Catalyst
- Oxidation of Iodine ions to Iodine.
- When the catalyst is in the same phase as the reactants
- 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)
- Oxidation of Ethanedioic Acid by Manganate (VII) Ions
- When one of the products of a reaction becomes a catalyst. This increases the rate rapidly as more of the catalyst is formed.
- Heterogeneous
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