Studied by 11 peoplechemical equilibrium (dynamic equilibrium)
two exactly opposite reactions are occuring simultaneously with the same rates of reaction
equilibrium constant (Kc, Kp)
the reaction quotient at equilibrium
reactant quotient (Q)
fraction relating the products ad reactants
at equilibrium are the concentrations of the chemical species equal
not necessiraly, they are constant
what states of matter are not included in an equilibrium equation
liquids and solids
if the K value is large
there are more products than reactants; reaction lies to the right
if the K value is small
there are more products than reactants; reaction lies to the left
Le Châtelier’s principle
if a chemical system at equilibrium is stressed, it will reestablish equilibrium by shifting the reactions involved
what are examples of stressors on equilibrium
changes in concentration, pressure, and temperature
are changes in pressure significant in all equilibrium reactions
no, only if gases are involved
if the volume a container decreases, how will the equilibrium system shift?
to the side with less moles of gas
if the volume a container increases, how will the equilibrium system shift?
to the side with more moles of gas
what factor changes the value of the equilibrium constant
temperature
heterogeneous equilibria
equilibria that involve more than one phase
homogeneous equilibria
systems in the gas phase, where all reactants and products are gases
what shift occurs when Q=K
no shift
what shift occurs when Q>K
shift right to left
what shift occurs when Q<K
shift left to righ
saturated solutions are at
equilibrium
shift right meaning
there are not enough products, so the system will shift to consume reactants and produce more products
shift left meaning
there are not enough reactants, so the system will shift to consume products and produce more reactants
what type of solution is at equilibrium
a saturated solution
if K >1, what side of the reaction is favored
products (forward reaction) is favored
if K is very large, describe the reaction
reaction goes essentially to completion
if K <1, what side of the reaction is favored
reactants (reverse reaction) are favored at equilibrium
if K is very small, describe the reaction
reaction barely proceeds at all
relate the K of the reverse reaction to that of the forward reaction
it is the reciprocal
when the equation of reaction is multipled by n, what happens to K
K is put to the nth power
when elementary steps are added together, the K of the overall reaction is
the product of the K’s of the elementary steps
if the pressure is increased, how will the equilibrium system shift?
to the side with less gas moles
if the pressure is decreased, how will the equilibrium system shift?
to the side with more gas moles
if an inert gas is added, how will the equilibrium system shift?
no effect
if heat is added to an endothermic reaction, how does K change?
K increases (K>1)
if heat is added to an endothermic reaction, how does the equilibrium system shift?
to the right (forward direction)
if heat is added to an exothermic reaction, how does K change?
K decreases (K<1)
if heat is added to an exothermic reaction, how does the equilibrium system shift?
shift to the left (reverse direction)
when concentration changed, the system will always shift away from
the added component
diluting always shifts towards which type of species
aqueous species
concentrating always shifts towards which type of species
less aqueous species
if the amount of a liquid or solid is changed in a system, how does the system react?
no change
how does adding a catalyst affect the equilibrium system?
no change
Ksp
solubility product constant
how does having more anions and cations affect the Ksp value?
the Ksp value is increased
solubility (s)
concentration of solid that dissolves
how does solubility affect the value of the equilbrium constant?
it has no effect, the attainment of equilibrium can be affected however
the Ksp of two salts can only be compared with
salts that fall into the same number of ions
a bigger Ksp value means
more soluble
when tow salts have a different number of ions, how can their solubilities be compared
by solving for solubility
what happens when Q is greater than the Ksp
precipitation
when happens when Q is less than the Ksp
no precipitate
common-ion effect
when a solid is dissolved in a solution with either the cation or anion already present, less solid will dissolve
how does the common-ion effect affect the Ksp?
no change
how does increasing pH affect the solubility of a salt?
decreases the solubility
how does decreasing pH affect the solubility of a salt?
increases the solubility
adding a substance that is not in the equilibrium equaiton increases the change of
a reaction with the substance
Note
Flashcard