1. Transition metals catalysts Catalysts lower activation energies allowing a chemical reaction to go faster. Heterogenous catalyst: different phase as reactants. Homogenous catalyst: same phase.

2. Transition metals as catalysts Transition metals are good catalysts because: o they have the availability of 3d and 4s electrons and similar successive ionization energies which allow them to change easily between different oxidation states (homogenous catalysis) o have empty orbitals which can be used to make temporary bonds (heterogenous catalysts).

3. Heterogenous catalysis Nickel in the conversion of alkenes into alkanes. Iron in the Haber process Manganese dioxide in the decomposition of hydrogen peroxide. Palladium and platinum in a catalytic converter. Cobalt in manufacture of vitamin B 12

4. Homogenous catalysis Overall: S 2 O 8 2 (aq) + 2I - (aq)  2SO 4 2- (aq) + I 2 (s) Using catalyst Fe 3+ 2Fe 3+ (aq) + 2I - (aq)  2Fe 2+ (aq) + I 2 (s) 2Fe 2+ (aq) + S 2 O 8 2- (aq)  2Fe 3+ (aq) + 2SO 4 2- (aq)