Unit 3 Equilibrium Review Flashcards
Le Chateliers principle
when a stress is applied to a system in dynamic equilibrium, the equilibrium will shift to relieve the stress
exothermic
energy is a product
ΔH is negative because you lose energy
endothermic
energy is a reactant
ΔH is positive because you gain energy
dynamic equilibrium
a state of balance in a CLOSED system at constant temperature and there are no changes at the visible level but there is a constant change at the molecular level
Closed system
a reaction system in which no matter can enter or exit. Only a closed system can reach an equilibrium.
Steady State
is an open system that has no properties that are directly observable; however, this is because any materials that leave the system are immediately replaced
three stresses that can be applied to an equilibrium system
concentration
temperature
volume/pressure
concentration [ ]
NO SOLIDS
shifts away from increase
shifts toward decrease
(arrow goes towards increase. ex:
↓ → ↑
temperature
shifts away from increase
shifts toward decrease
(arrow goes towards increase. ex:
↓ → ↑)
volume/pressure
GASES ONLY
increase pressure favours side with less moles
increase volume favours side with more moles
catalysts
catalyst is a substance that speeds
up the rate of reaction without being used up in the reaction.
*Catalysts will NOT have any effèct on an equilibrium position because they speed up the reaction equally in both directions.
concentration graph
vertical line and a hill
temperature graph
all hills
pressure graph
all vertical lines
keq
[products]/[reactants]
keq is only
gases and aqueous
no solids or liquids
if keq is larger than 1
A value for Keq significantly.
larger than one means that products are favored over reactants.
if keq is less than one
A value of Keq significantly less than one it means that reactants are favoured over products
if keq is very close to 1
A value of Keq very close to 1 means that the (reactant] ~ [product)
spontaneous
products are favoured
large equilibrium constant (keq)
> > > > > 1
non spontaneous
reactants are favoured
small equilibrium constant
««1
ICE charts
Initial: if not known, put 0
Change: + or - ___x (one side will be +, one side will be -) (__x will be the # in front of chemical)
Equilibrium: if not given is I + C
dissociation
is reversible physical change
net ionic
the non reversible chemical change where an insoluble ppt is formed
