Catalysts Flashcards
What is a catalyst?
speed up reaction
remains unchanged
Why is it cheaper to use a catalyst rather than high temperatures and pressures?
because they are not used in the reaction, they can be reused
it is more energy efficient
stronger equipment is needed to handle the high pressures and temperatures
How do catalysts work?
they provide a different pathway for the reaction, one with lower activation energy
therefore they reduce the activation energy of the reaction
What is the equation, catalyst and uses for the Haber process?
N2(g) + 3H2(g) -> 2NH3(g)
iron
making ammonia fertilisers
What is the equation, catalyst and uses for the Ostwald process?
4NH3 + 5O2 -> 4NO + 6H2O
platinum and rhodium
making fertilisers and explosives
What is the equation, catalyst and uses for the process of hardening fats?
H2C=CH2 + H2 -> CH3CH3
C2H4 + H2 -> C2H6
nickel
making margerine
What is the catalyst and uses for cracking hydrocarbon chain from crude oil?
aluminium oxide and silicon dioxide zeolite
making petrol
What is the catalyst and uses for the catalytic converter reactions in car exhausts?
platinum and rhodium
removing polluting gases
What is the equation, catalyst and uses for the hydration of ethene to produce ethanol?
H2C=CH2 + H2O -> CH3CH2OH
C2H4 + H2O -> C2H5OH
H+ absorbed on solid silica phosphoric acid, H3PO4
making ethanol
a fuel additive, solvent and chemical feed stock
What is the equation, catalyst and uses for esterification?
CH3CO2H(l) + CH3OH (l) -> CH3CO2CH3(aq) + H2O(l)
H2H5O2(l) + CH3OH (l) -> C3H6O2(aq) + H2O(l)
H+
making solvents
What are catalytic converters?
all petrol engine cars are now equipped with catalytic converters that reduce the levels of polluting gases
honeycomb, made of ceramic material coated with platinum and rhodium metals
honeycomb shape provides a large surface area for the reaction to take place
What are the reactions for a catalytic converter?
carbon monoxide + nitrogen oxide -> nitrogen + carbon dioxide
hydrocarbons + nitrogen oxides -> nitrogen + carbon dioxide + water
What are the step for the reaction to take place on the surface of the catalyst?
gases first form weak bonds with the metal atoms of the gases - adsorption, holds the gases in just the right position for them to react together
products break away from the metal atoms - desoption, this frees up room on the catalust surface fore more gases to take their place and react
Error - state the meaning of a catalyst and how they work
chemically unchanged substance that lowers the activation energy by providing an alternative pathway for the reaction
Why is the reaction faster with a catalyst?
Ea lowered by alternative route
more molc have the activation energy
