Ap Chemistry: Le Chatelier's principle + unknown concentrations Flashcards
What does leChatelier’s principle state
when stress is applied to a reaction at equilibrium, the reaction will shift in a direction to release the stress
What is the “stress”
anything that will cause us to not have products and reactants be in a ratio related to Kc
What are the types of stresses
volume, pressure, temperature(heat), molarity
On a graph how do you know when equilibrium is reached
when the line is a straight line
what happens to Qc when you add more reactants; where will it shift
Qc
what happens to Qc when you add more products; where will it shift
Qc>k; shift to the reactants to level it out
what happens when we remove products from the mixture
Qc
what happens when we remove the reactants from the mixture?; where will it shift
Qc>K; and the reaction will shift toward the reactants to replace what was lost
how can you dilute concentrations in a reaction
add water
what would happen to the molarities of the aqueous solutions
they would decrease
what will cause a no change in the equilibrium
when the moles of the aqueous = moles of the water
what happens when the equation has two sides of unequal moles, where will the water shift?
the reaction would shift to the side with more moles
What happens to the volume when you increase pressure, and where will it shift?
decrease the volume; shift to the side with fewer moles
what happens to the volume when you decrease the pressure? where will it shift
increase the volume; shift to the side with more moles
what happens when moles of gas are equal on both sides?
there is no shift
what does it mean when a reaction is endothermic
heat is a reactant or heat + reaction = products
what does it mean when a reaction is exothermic
heat is a product or reaction = products + heat
what is the goal of Le Chatelier in regards to temperature changes?
Get the reaction to a New Kc
if the temperature increased in an endothermic reaction, what will happen to k, and where will it shift toward
K will increase and it will shift to the products
if the temperature increased in an exothermic reaction, what will happen to k, and where will the reaction shift
K will decrease and it will shift towards the reactants
if the temperature decreased in an endothermic reaction, what will happen to K, and where will the reaction shift?
K will decrease; shift towards reactants
if the temperature decreased in an exothermic reaction, what will happen to K, and where will the reaction shift
K will increase; shift towards the products
does a catalyst affect the equilibrium?
No
if an initial concentration is not given, what do you use?
x
