Chap 7: Equilibrium Flashcards
(16 cards)
What is th le chatelier’s principle
if an external stress is applied to a chemical system at equilibrium, the rates of the forward and reverse reactions are temporarily unequal because the stress affects the reaction rates; however, equilibrium is eventually restored in the chemical system
what are the different external stressors
conc, pressure, volume, and temp
what happens when the conc of a product is increased
increasing conc of a product causes a shift left (to reactants)
what happens when the conc of a product is decreased
decreasing conc of a product causes a shift right (to products)
what happens when the conc of a reactant is increased
increasing conc of a reactant causes a shift right
what happens when the conc of a reactant is decreased
decreasing conc of a reactant causes a shift left
is Keq affected by conc changes?
NO as equilibrium is reestablished
what happens when pressure increases
when pressure increases (volumes decreases), the rxn shifts so that the total number of particles decreases which decreases the pressure in the system
what happens when pressure decreases
when pressure decreases (volume increases), the rxn shifts so that the total number of particles increases, which increases the pressure in the system
what happens when you add an inert gas
adding an inert, although it increases pressure, it does NOT shift the equilibrium
is Keq affected by pressure and volume changes
no as equilibrium is re-established
what does a temp increase favour
a temp increase favours the endothermic reaction (heat absorbing)
what does a temp decrease favour
a temp decrease favours the exothermic reaction (heat releasing)
what happens to Keq in an endothermic system
in an endothermic system (endo in the forward direction), an increase in temp increases Keq
What happens to Keq in an exothermic system
in an exothermic system (exo in the forward direction), an increase in temp decreases Keq
How does a catalyst affect the equilibrium
the presence of a catalyst does not shift equilibrium in either direction
