Direction of Change Flashcards
Spontaneous (in forward direction)
reactants change to products
Not spontaneous (spontaneous in reverse direction)
products change to reactants
Standard state
a commonly accepted set of conditions used as a reference point
What are the standard state conditions?
1 bar/atm, 1M, pure solid, pure liquid, NOT STP, no temp value specified
ICE table
a way to determine equ concentrations and the change in concentration
What units are used in ICE tables?
M, bars, or atm
Reaction quotient (Q)
gives spontaneity of reaction; same expression as K
When is Q used?
if it is not known if we are at equilibrium or we know we are not at equilibrium; determined at a specific time
What happens when Q=0?
only reactants are present
What happens when Q=K?
the reaction is at equilibrium
What happens when Q<K?
the reaction proceeds in the forward direction
What happens when Q>K?
the reaction proceeds in the reverse direction
Le chatlier’s principle
when a chemical system is at equilibrium and conditions are changed so that the reaction is no longer at equ, the system reacts to achieve new equ concentrations in a way that partially counteracts the change in conditions
What happens if volume is increased in a system?
the pressure decreases, and moles increase, so it shifts to the side with fewer gaseous moles
What happens if volume is decreased in a system?
The pressure increases and moles decrease, so it shifts to the side with more gaseous moles
