10.2 Catalysts

Question 1

How does a catalysts increase the rate of a reaction

Answer 1

provides an alternate reaction pathway with a lower activation energy so a greater proportion of molecules exceed the activation energy

Question 2

What is a catalyst

Answer 2

a substance that increases the rate of a chemical reaction without undergoing any permanent change itself

Question 3

Features of catalyst

Answer 3

-not used up in the chemical reaction
-may react with a reactant to form an intermediate or may provide a surface on which the reaction can take place
-at the end of the reaction the catalyst can be regenerated

Question 4

What is a homogenous catalyst

Answer 4

a catalysts that has the same physical state as the reactants

Question 5

How does a homogenous catalyst work?

Answer 5

the catalyst reacts with the reactants to form an intermediate. the intermediate then breaks down to give the product and regenerates the catalyst

Question 6

Examples of homogenous catalyst

Answer 6

-making esters with sulfuric acid as the catalyst
-ozone depletion with Cl radicals as the catalyst

Question 7

Examples of homogenous catalyst

Answer 7

-making esters with sulfuric acid as the catalyst
-ozone depletion with Cl radicals as the catalyst

Question 8

What is a heterogenous catalyst

Answer 8

a catalyst that has a different physical state from the reactants

Question 9

How does a heterogenous catalyst work

Answer 9

-usually solids in contact with gaseous reactants or in a solution
-reactant molecules are absorbed onto the surface of a catalyst where the reaction takes place
-after the reaction, the product molecules leaves the surface of the catalyst by desorption

Question 10

Examples of heterogenous catalyst

Answer 10

-making ammonia with Fe as the catalyst
-reforming Pt or Rh as the catalyst
-hydrogenation of alkenes with Ni as catalyst
-Making sulfur trioxide for sulfuric acid with V2O5 as catalyst

Question 11

What is the sustainability and economic importance of catalysts

Answer 11

-by lowering the activation energy of a reaction this reduces the temperature needed for a reaction to occur and reducing the energy demand
-became the chemical process requires less energy there is less electricity and fossil fuels used, CO2. emissions decrease
-making products faster and using less energy can cut costs and increase profitability
-different reactions can be used with greater atom economies (which reduces the use of toxic solvents and reactants
-generate specific products