Catalytic Properties and Uses of Transition Metals

Give examples of some transition metals which are used as catalysts and name the process in which they are used.

• Iron in the Haber process.

• Nickel to make margarine from the hydrogenation of vegetable oils i.e. alkenes.

• Vanadium(V) oxide in the contact process.

• Manganese(IV) oxide in the catalytic decomposition of hydrogen peroxide.

What are the 2 types of catalysts?

• Homogenous

• Heterogenous

What is a homogenous catalyst?

Homogeneous catalysts are in the same physical state as the reactants.

How do homogenous catalysts work?

• They work by using their variable oxidation states to oxidise/reduce a reactant, making it more reactive.

• The transition metal can then be converted back to its original oxidation state by reaction with another molecule.

What is a heterogenous catalyst?

Heterogeneous catalysts are in a different physical state to the reactants.

How do heterogenous catalysts work?

• They work by having partially filled d orbitals.

• The catalyst provides a solid surface on which reactants can be adsorbed and brought closer together for more opportunity to react.

• Molecules with lone pairs can form coordinate bonds to the metal atom because there are available empty d orbitals to bond with.

Give examples of transition metals which are present in trace amounts in biological systems.

• Iron- present in haemoglobin which carries oxygen around the body.

• Cobalt- a component of vitamin B12.

State the economic importance of some transition metals.

• Chromium- a component of stainless steel.

• Iron- used in iron and steel manufacture for construction.

• Copper- used in circuitry and electronics.