Catalysis

Question 1

What shape is Cis-Platin

Answer 1

Square planar

Question 2

Why is only Cis-Platin used in cancer treatment

Answer 2

Cis-Platin has anti cancer properties = Trans form is much less effective and is more toxic

Using only one isomer reduces risk of harmful side effects

Question 3

What type of ligand is EDTA 4-

Answer 3

Multidentate ligand

Question 4

What is the EDTA 4- ligand similar to

Answer 4

NH2CH2CH2NH2

Question 5

What is haemoglobin

Answer 5

Protein in red blood cells = carries oxygen

It’s a Fe2+ complex contains a monodentate ligand

Question 6

How does carbon Monoxide effect haemoglobin

Answer 6

Carbon atom has a lone pair of electrons = acts as ligand

Binds to haemoglobin more strongly than oxygen does = ligand exchange happens

Question 7

Heterogeneous catalyst

Answer 7

Catalyst in different phase from reacts

Question 8

Describe role of heterogenous catalyst action - Adsorption,Reaction, Desorption

Answer 8

1- Adsorption of reactants onto surface of catalyst

2- catalyst weakens bonds + orientates reactants

3- Desorption of products from surface

Question 9

Catalytic poisoning

Answer 9

Reactants/Products adsorbed too strongly into active sites on surface of catalyst

= blocks Adsorption of reactants

Eg: Lead poisons Veichle catalytic converters reducing efficiency

Question 10

What process is Sulphuric acid manufactured in and what catalyst is involved

Answer 10

Contact proscess

Catalyst = Vanadium Oxide V2O5

Question 11

Show the second stage of contact proscess

Answer 11

SO2 + 1/2 O2 = SO3

Question 12

Show the redox reactions with the catalyst V2O5 in second stage of contact proscess

Answer 12

V2O5 + SO2 = V2O4 + SO3
+5 = +4

Catalyst remade by:

V2O4 + 1/2 O2 = V2O5
+4 = +5

Overall oxidation stage of vanadium is unchanged = SO2 is oxidised by O2 + SO3

Question 13

Show the equation for the action of catalytic converters on harmful gasses of CO + NO

Answer 13

CO + NO = CO2 + 1/2 N2

Question 14

Describe action of catalyst in catalytic converters- NO + CO

Answer 14

CO + NO molecules adsorbed onto surface of catalyst

Bonds in molecules weaken + chemical reaction occurs

CO2 + N2 produces and desorption from surface of catalyst

Question 15

Homogenous catalyst

Answer 15

Catalyst in same phase as reactants

Question 16

Why are catalysts needed in reactions for : I- + S2O8(2-) and MnO4- + C2O4(2-)

Answer 16

Both reactant species are negatively charged = they repel each other leading to : High activation energy + Low rate of reaction at room temp

The catalysts are positively charged = attract reactant species and go via an intermediate

Question 17

What homogeneous catalyst is needed for S2O8(2-) + I(-)

Answer 17

Fe2+

Question 18

Show the 2 steps in reaction of S2O8(2-) + I(-)

Answer 18

Question 19

Write an equation for reaction between MnO4- + C2O4(2-)

Answer 19

2MnO4(-) + 5C2O4(2-) + 16H+ = 2Mn2+ + 10CO2 + 8H20

Question 20

What is a auto catalyst

Answer 20

Product of reaction acts as a catalyst for the reaction

Question 21

Show the 2 steps in reaction between MnO4- + C2O4-
Catalysted by autocatalyst = Mn2+

Answer 21