Table

quantity

symbol

represents

positive means

negative means

spontaneity

enthalpy change

ΔH

heat absorbed/released at constant pressure

endothermic: system gains heat from surroundings and feels cold

exothermic: system releases heat to surroundings (feels hot)

spontaneous if negative

entropy change

ΔS

change in disorder of system

more disorder

more order

spontaneous if positive

gibbs free energy change

ΔG

driving force for a process at constant temperature and pressure

non-spontaneous

spontaneous

if its negative its spontaneous, if its positive its not spontaneous

cell potential

E°_^cell

voltage of a redox reaction

galvanic cell, spontaneous, produces electricity

electrolytic cell, non spontaneous, needs external power

if its positive spontaneous, if its negative non spontaneous

equilibrium constant

k

ratio of products/reactants at equilibrium

products favored

reactants favored