Chem 30 Unit 3 Flashcards
(46 cards)
Equilibrium
a state of a closed system in which all measurable properties are constant
Dynamic equilibrium
a balance between forward and reverse processes occurring at the same rate
Ice tables
Initial, Changes, Equilibrium
in an ice table…
Products always start at zero
Reactants go down; products go up
<50% reaction =
reactants favoured, reverse reaction, k <1
> 50% reaction =
products favoured, forward reaction, k>1
> 99% reaction =
quantitative, complete reaction, k is a very large number
if there is no reaction
k = 0
when is a reaction quantitative (arrow)?
single arrow
what to not include in K value calculations?
a solid in a gas reaction or water (l) in an aqueous solution reaction)
Le Chatelier’s Principle
disturbed close systems will shift to restore equilibrium
Le Chatelier’s Principle says…
Conditions affecting equilibrium are temperature, pressure, and concentration
3 stages of Le Chatelier’s
Initial equilibrium state, Shifting non-equilibrium state, New equilibrium state
in concentration shifts…
k value remains constant
in temperature shifts…
k value changes
in an endothermic reaction…
when temp increases, k value increases, vice versa
in an exothermic reaction…
when temp increases, k value decreases, vice versa
pressure/volume shifts
k value remains constant. (pressure/volume shifts are only for gases)
Pressure increase/volume decrease:
shift towards the side with fewer moles of molecules
Pressure decrease/volume increase:
shift towards the side with more moles of molecules
when there is equal moles on each side and a volume/pressure shift…
no change occurs / no shift
a catalyst…
Changes the rate of both forward and reverse reaction by the same amount, therefore it does not affect the position of the equilibrium.
If inert gases are added to increase the total pressure of the system…
nothing will change. The equilibrium pressure will not change.
pH/pOH sig digs
the numbers behind the decimal place are significant
