Topic 9 Kinetics I

Question 1

Heterogeneous catalyst is often a porous material, so it…..

Answer 1

Increases SA for adsorption

Question 2

How does increase in temp change the Maxwell-Boltzmann curve?

Answer 2

Peak shifts right and lowers

Question 3

What is the activation energy/enthalpy? 2 marks

Answer 3

The minimum energy (1) required for a reaction to occur
For successful collisions (1)

Question 4

How do catalysts change the Maxwell-Boltzmann curve?

Answer 4

No change in curve
Lower activation energy, more particles (area) under Ea line and curve

Question 5

Gaseous reactants attach to the catalytic surface by the process of….

Answer 5

Adsorption

Question 6

why is it good for industries to use catalysts?

Answer 6

increases RoR, decreasing time a reaction to take place
so lowers cost in milder conditions

Question 7

How do heterogeneous catalysts work? (4 marks)

Answer 7

Reactants adsorb onto catalyst
There are Active sites on catalyst surface
Bonds in reactants lengthened/weakened/broken
Products desorb from catalyst

Question 8

What is the use of cotton wool on conical flask when reacting substances?

Answer 8

Prevent loss of acid spray

Question 9

Why does mass in conical flask (reacting HCl and marble chips) decrease during the course of experiment? When there is cotton wool on top

Answer 9

CO2 produced, released and escapes through cotton wool

Question 10

How does a catalyst work? 2 marks

Answer 10

Provides alternative pathway
Lowering activation energy