Chapter 15 - Equilibrium Flashcards
A system at equilibrium
The amount if reactants and products remains constant
Chemical equilibrium
Occurs when a rxn and its inverse rxn proceed at same rate
As syst approaches equilibrium both forward and reverse rxns are occurring
Can be reached from either direction
Same rate at equilibrium
Keq
Kf(x) = Kr(y)
For equilibrium to occur
Nothing can escape system
Particular ratio of concentrations equals constant
K»1
Rxn is product favored (products predominates at equilibrium)
K«1
Rxn is reactant favored (reactant predominates at equilibrium)
Manipulating equilibrium constant
Rxn in reverse has 1/k as the constant
Heterogeneous equilibrium
Concentrations of solids and liquids are essentially constant so DO NOT appear in equilibrium process
The reaction quotient
Q gives the same ratio equilibrium expression gives but for a system not a equilibrium
Substitute initial concentrations into equilibrium expression
Q>k
Too much product
Q<k
Too much reactant
Le chateliers principle
If a system at equilibrium changes in temp, pressure, or concentration of one component the system will shift to counteract disturbance
Haber process
Transformation of nitrogen and hydrogen into NH3 (fertilizers)
Catalysts
Increase both rates of forward and reverse rxns
Equilibrium is achieved faster but composition remains unaltered
