Catalysts

Question 1

Catalysts

Answer 1

Change rate of chemical reaction without undergoing permanent change itself
Not used up in reaction
May react to form intermediate, or provide surface on which reaction takes place
Catalyst regenerated
Provides alternative pathway, lower activation energy

Question 2

Homogenous catalyst

Answer 2

Same physical state as reactant

Reacts to form intermediate, breaks down, gives product, regenerated

Question 3

Heterogenous catalyst

Answer 3

Different physical state from reactants
Usually solid in contact with gaseous reactants or in solution
Reactant molecules adsorbed onto catalyst surface, reaction takes place
After reaction, product leaves catalyst surface by desorption

Question 4

Industrial processes that use heterogenous catalysts

Answer 4

Haber process N2+ 3H2 <=> 2NH3
Reforming C6H14 => C6H12 + H2
Hydrogenation of alkenes C2H4 + H2 => C2H6
Contact process 2SO2 +O2 <=> 2SO3

Question 5

Heterogenous catalysts and pollution

Answer 5

Catalytic converters, platinum, rhodium, palladium on honeycomb mesh, LSA for reactions
Hot exhaust fumes passed over catalyst, harmful gases converted into less harmful products
CO, NO, Hydrocarbons changed into N2, CO2, H2O

Question 6

Catalysts, sustainability and economic importance

Answer 6

90% of all chemical materials produced w catalyst
Reduces temperature needed, lower AE
Reduces fuel costs, increase profitability
Advantages outweigh costs associated with development of catalyst process
Fewer fossil fuels, reduce CO2 emissions

Question 7

Autocatalysis

Answer 7

Product acts as catalyst for reaction
Reaction starts slowly, no catalyst
Speeds up r of r after cat produced