10.2 Catalysts Flashcards
(10 cards)
What is a catalyst?
A substance that changes the rate of a chemical reaction without undergoing any permanent change itself.
What do catalysts chemically do in a reaction? (Not activation energy related)
-Provide a surface on which the reaction can take place
-React with a reactant to form an intermediate
What is an intermediate?
A species formed during a reaction that reacts further, and is not present in the final products.
How does a catalyst increase the rate of a chemical reaction?
By providing an alternative reaction pathway of lower activation energy
What is a homogeneous catalyst?
A catalyst that has the same physical state as the reactants
Give examples of homogeneous catalysts.
-Producing esters with sulfuric acid as a catalyst
-Ozone depletion with a Cl* radical as a catalyst
What is a heterogeneous catalyst?
A catalyst that has a different physical state from the reactants (typically a solid)
What does a heterogeneous catalyst do?
-Reactant molecules are absorbed onto the surface of the catalyst, where the reaction takes place
-After reaction, the product molecules leave the surface of the catalyst by DESORPTION
What is the benefit of using catalysts in industrial processes?
Lowers the activation energy, so less energy required, so less electricity or fossil fuel is used up.
If air is needed in a reaction, why might it be purified before being added to a reaction involving a catalyst?
To remove catalytic poisons
