Inorganic Chemistry 3.3 - Transition Metals - Catalysts

Question 1

Transition metals and their compounds can act as either ___ or ___ catalysts.

Answer 1

heterogeneous, homogeneous

Question 2

Homogeneous catalysts are…
Heterogeneous catalysts are…

Answer 2

in the same state as their reactants.
in a different state to their reactants

Question 3

Heterogeneous catalysts can be explained by the formation of…

Answer 3

activated complexes

Question 4

Heterogeneous catalysation involves ___ of the molecule undergoing reaction onto the active site, and then subsequent ___, and ___.

Answer 4

adsorption, reaction, desorption

Question 5

Define the following terms:
1. Adsorption
2. Reaction
3. Desorption

Answer 5

Adsorption is the binding of the reactant onto the active site of the T metal catalyst
Reaction involves bonds within the reactant breaking, and new bonds between the reactant and catalyst forming (ie the formation of an activated complex)
Desorption is when the product leaves the active site.

Question 6

What property of transition metals allows the formation of activated complexes, and therefore enables them to act as catalysts?

Answer 6

unfilled d orbitals / unpaired d electrons

Question 7

The formation of activated complexes provides reaction pathways with…

Answer 7

lower activation energies

Question 8

Homogeneous catalysts can be explained in terms of variable ___ ___ and the formation of ___ ___.

Answer 8

oxidation states, intermediate complexes

Question 9

Summarise the two types of transition metal catalysts.

Answer 9

1. Heterogeneous - reactant molecules adsorb to, react on, and then desorb from the active site of the catalyst. An activated complex is (temporarily) formed, providing a reaction pathway with a lower activation energy.
2. Homogeneous - intermediate complexes form, providing reaction pathways with lower activation energies. The variable oxidation state of transition metals enables the formation of intermediate complexes.