Le Chateliers Principle Flashcards
(22 cards)
what does Le Chateliers principle state
that if an equilibrium system is subjected to a change so that is no longer at equilibrium, the system will adjust itself to partially oppose the effect of the change
what does partially oppose mean
the system does not fully counteract the change, it adjusts itself through a net reaction, that will reduce the impact of this change and establish a new equilibrium
what does it mean when the position of equilibrium shifts to the left
the concentration of the reactants increases
what does it mean when the position of equilibrium shifts to the right
the concentration of the products increases
for any equilibrium system, what can change the position of the equilibrium
adding or removing reactant or product, changing pressure by changing volume, dilution, changing temperature, adding substance that reacts with reactant/product
how to chemists maximise equilibrium yield
through careful control of the reaction conditions, moving the position of the equilibrium to the right
how does equilibrium shift when there is an increase in the concentration of a REACTANT
equilibrium shifts to the shift, forward reaction prioritised
how does equilibrium shift when there is a decrease in the concentration of a product
equilibrium shifts to the right, forward reaction favoured
how does equilibrium shift when there is an increase in the concentration of a product
equilibrium shifts to the left, backward reaction favoured
how does equilibrium shift when there is a decrease in concentration of reactants
equilibrium shifts to the left, backward reaction favoured
what will the concentration vs time graph look like for a change in concetration through adding/removing product/reactant
sharp increase/decrease for the changed reactant/product, all slope down/up to partially oppose the change in their relative mole ratios
what happens to the equilibrium and why of a reaction vessel if the volume is decreased
the pressure will increase, leading to a higher concentration of of particles per unit volume, hence the reaction will shuft toward the side that produces fewer molecules, which decreases concentration and pressure
what happens to the equilibrium and why of a reaction vessel if the volume is increased
the pressure will decrease, leading to a lower concentration of of particles per unit volume, hence the reaction will shuft toward the side that produces more molecules, which increases concentration and pressure
what does the concentration vs time graph look like for a volume increase/decrease
all products/reactants have a sharp decrease/increase, all slope up/down to partially oppose this change
how can pressure be changed not through changing volume
by adding an inert gas
does changing pressure through adding an inert gas change equilibrium
no as this gas does not change the concentration of the reactants/products so there is no effect on the position of equilibrium
how does dilution affect equilibrium
the addition of an unreactive solvent, which decreases the concentration of the reactants and products will cause the system to favour the reaction that produces more particles
what is the effect of increasing temp on the position of equilbrium
shifts in the direction of the endothermic reaction as this absorbs energy/heat is added to reactants side
what is the effect of decreasing temp on the positoon of equilibrium
shifts in the direction of the exothermic reaction as this absorbs energy/heat is added to products side
what does the time vs concentration graph look like for tempertaure increase/decrease
no spike, the products/reactants experience gradual changes based on endo.exo
do catalysts affect the position of equilibrium
no, they only increase the rate at which equilibrium is reached
why does a catalyst not affect the position of equilibrium
because the catalyst increases the rate of reaction for the forward and backward reactions by the same amount
