15.2.2 Gibb's Free Energy

the measure of the energy that is free to do useful work rather than just leave the system as heat

what is gibb’s free energy

enthalpy gives the quantity of heat change while gfe gives the quality of available energy

what is the difference between the measures of enthalpy and gfe

negative

is a process is spontaneous, what is the sign for g

hess’ law, products-reactants, G=H-TS

what are the three ways to calculate g

always spontaneous

what is the effect on spontaneity with neg H and pos S

spontaneous at low temperatures

what is the effect on spontaneity with neg H and neg S

spontaneous at high temperatures

what is the effect on spontaneity with pos H and pos S

never spontaneous

what is the effect on spontaneity with pos H and neg S

when a reaction mixture is at the minimum value of gibb’s free energy

when does equilibrium occur

when the rate of the forward reaction is the same as the rate of the reverse reaction

when does equilibrium exist

the reaction is spontaneous and proceeds forward (product favoured)

what happens when g is negative

the reaction is non spontaneous and proceeds backwards (reactant favoured)

what happens when g is positive

the reaction is at equilibrium

what happens when g is zero