10.2 Catalysts Flashcards
How does a catalysts increase the rate of a reaction?
Provides an alternate reaction pathway with a lower activation energy so a greater proportion of molecules exceed the activation energy
What is a catalyst?
A substance that increases the rate of a chemical reaction without undergoing any permanent change itself
What are features of catalysts?
-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
What is a homogenous catalyst?
A catalyst that has the same physical state as the reactants
How does a homogenous catalyst work?
The catalyst reacts with the reactants to form an intermediate. the intermediate then breaks down to give the product and regenerates the catalyst
Examples of homogenous catalyst
-making esters with sulfuric acid as the catalyst
-ozone depletion with Cl radicals as the catalyst
What is a heterogenous catalyst?
A catalyst that has a different physical state from the reactants
How does a heterogenous catalyst work?
-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
Examples of heterogenous catalyst
-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
What is the sustainability and economic importance of catalysts?
-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
Draw a reaction profile for an exothermic reaction with and without a catalyst
Draw a reaction profile for an endothermic reaction with and without a catalyst
What are benefits of homogenous catalysts
