Transition metal catalysts Flashcards
Why do transition metals make good catalysts?
They have variable oxidation states so they can transfer electrons to speed up reactions
What is the overall equation for the contact process?
SO2 + 1/2O2 -> SO3
What is the first stage of the contact process?
V₂O₅ + SO₂ -> V₂O₄ + SO₃
What is the second stage of the contact process?
V₂O₄ + ¹/₂O₂ -> V₂O₅
What is a heterogeneous catalyst?
One that is in a different phase from the reactants
What is the equation for the haber process?
N₂ + 3H₂ -> 2NH₃
Where do the catalysed reaction take place on a heterogeneous catalyst?
On the surface of the catalyst
What is a support medium?
Used to make the area of a catalyst as large as possible
What does adsorbed mean?
Stuck on the surface
What is catalyst poisoning?
Impurities in the reaction binding to the catalyst’s surface and block reactants from being adsorbed
What is the issue with catalytic poisoning?
- Reduces the surface area of the catalyst available to the reactants, slowing down the reaction
- Increases the cost of a chemical process because less product can be made in a certain time or with a certain amount of energy
Which type of catalyst is affected by catalyst poisoning?
Heterogenous catalyst
How can catalyst poisoning be reduced?
By purifying the reactants, removing the impurities
What are homogeneous catalysts?
Catalysts in the same state as the reactants
How do homogeneous catalysts work?
Forming an intermediate species which the reactants combine with, which forms the product and the catalyst is then reformed
