3.2.3 Chemical equilibrium

reversible reactions

reactions in which the roducts of a reaction cna react together to reform the original reactants,rereseneted sing a double arrow one reaction direction endothermic and one exothermic

dynamic equilbirium

• exists in a closed system

• where rate of forwards reaction is equal to rate of reverse reaction,

• concentrations of reactants and products remain constant

le chatelier rincile

when a system is subject to a change in conditions the osition of equilbirium will shift to lessen the effect of that change

changign temerature effect on equilibrium osition

if you increase temperature the osition of equilibtium will shift to favour endothermic reaction +H

changing ressure affect on equilbirum osition

increasing ressure favours side of the reaction with fewer gaseous moles

changing concentration effect on equilbrium osition

increaseing concentration of reactants will favour forward reaction roducing roducts so more roducts

catalyst effect on equilibrium

no effect on equilbrium osition

comromise between rate of reaction and roduct yield

• some conditions change which roduce a higher orortion of roduct may also reduce rate of reaction

• high ressure and temerature exensive

• low ressure and tempertaur low rate

how toinvestigate equilibrium osition

changes in colour

equilibrium constant Kc

indicates oition of equilibrim for a reacion at a certain temerture

kc calculation

product 1]^moles x (product 2]^moles / (reactant 1]^moles x (reactant 2]^moles

how to find out units

sub in mol dm^-3 and then cancel out

what is value of kc affected by

temerature change

how can equilibrium osition be estimated by kc

large value of Kc indicate equilibrium to right and more products and small value indicates to left and more reatcats