topic 4 - reversible reactions and equilibria Flashcards
reversible reaction
a reaction where the products can react with each other to produce the original reactants
A + B ⇌ C + D
dynamic equilibrium
the point in a reversible reaction when the rates of the forward and backwards reactions are the same
concentration when in dynamic equilibrium
concentration of reactants and products has reached a balance and won’t change
dynamic equilibrium can only occur in what kind of system
closed
closed system
a system where none of the reactants or products can escape
what is still happening in dynamic equilbrium
both reactions are still happening but there is no overall effect
what affects the EXACT position of equilibrium
depends on the reaction itself and the conditions
what 3 things can change the position of equilibrium
temperature
pressure
concentration
le chatelier’s principle
if there is a change in concentration, pressure or temperature in a reversible reaction, the equilibrium position will move to help counteract that change
how does temperature affect position of equilibrium
if temperature INCREASES, equilibrium shifts to favour the endothermic reaction to absorb the extra heat
if temperature DECREASES, equilibrium shifts to favour the exothermic reaction to produce more heat
how does pressure affect position of equilbrium
ONLY AFFECTS EQUILIBRIA INVOLVING GASES
if pressure INCREASES, equilibrium moves to favour the side with fewer moles of gas to reduce pressure
if pressure DECREASES, equilibrium moves to favour the side with more moles of gas in order to increase pressure
how does concentration affect position of equilibrium
if you increase concentration of the REACTANTS, equilbrium shifts to the right to use up the reactants
if you increase the concentration of the PRODUCTS, equilibrium shifts to the left to use up the products
(decreasing concentration has the opposite effect)
