Catalysts

Question 1

What is a catalyst?

Answer 1

A substance that increases the ROR without undergoing any permanent change during the reaction

Question 2

How does a catalyst work?

Answer 2

• It lowers Ea by providing an alternative pathway

- It doesn’t get used in the reaction

Question 3

What is a homogeneous catalyst?

Answer 3

• Same physical state as the reactants.
• The catalyst reacts w/ the reactants to form an intermediate.
• Intermediates then breaks down to give the product + regenerates the catalyst.

Question 4

Give an example of a homogeneous catalyst

Answer 4

• Making esters with sulphuric acid as a catalyst

- Ozone depletion

Question 5

What is the process for making esters with sulphuric acid?

Answer 5

H2SO4(l)
—>
C2H5OH(l) + CH3COOH(l) CH3COOC2H5(l) + H2O

Question 6

What is the process of ozone depletion?

Answer 6

Cl radical (Cl r)as a catalyst
Cl r(g)
–>
2O3(g) 3O2(g)

Question 7

What is a heterogeneous catalyst?

Answer 7

• different physical state from reactants

- usually in solids in contact w/ g reactants/products in solution

Question 8

What are the examples of heterogeneous catalyst?

Answer 8

• Making ammonia (Harber process) reversible
  Catalyst = Fe(s)
  Equation+ N2(g) + 3H2(g) ——> 2NH3(g)
• Reforming
  Catalyst = Pt(s) or Rh(s)
  Equation = C6H14(g) —-> C6H12(g) +H2
• Hydrogenation of alkenes
  Catalyst = Ni(s)
  Equation = C2H4(g) +H2 —-> C2H6(g)

-Making sulphur trioxide for sulphuric acid reversible
Catalyst = V2O5
Equation = 2SO2(g) +O2(g) ——> 2SO3(g)

Question 9

The process of Heterogeneous catalyst?

Answer 9

• Reactant molecules are adsorbed (weakly bonded) onto the surface of the catalyst, where the reaction takes place
• After reaction, the product molecules leave the surface of the catalyst by desorption.

Question 10

How do catalyst have great economic importance and benefits?

Answer 10

• Increases ROR by lowering Ea
• Reduces the temp so less energy, less electricity/fossil fuel (cut CO2 emissions)
• Making the product faster + using less energy = cheaper and increases profitability

Question 11

How do catalyst have great economic importance and benefits?

Answer 11

• Increases ROR by lowering Ea
• Reduces the temp so less energy, less electricity/fossil fuel (cut CO2 emissions)
• Making the product faster + using less energy = cheaper and increases profitability
• sustainable reactions = higher atom economy