Cliffs AP Chemistry, 3rd Edition

∆G= ∆G°+ RT⋅ln Qwhere Q= reaction quotient

∆G= ∆G°+ 2.303 RT log K

∆G°= −n F E°

where F = Faradays

1 F = 96,500 J ⋅mole–^1 ⋅V–1

E°= standard cell potential, volts (V)

n= number of electrons in the half-reaction

plogTT

1

∆SC=2 303.^2

2 303. RT T log

HT T

K

K

12

21

T

T 2

:: 1

• =

∆ %^h

where R = 8.314J ⋅K –1

• Temperature’s Effect on Spontaneity: ∆G°= ∆H°−T∆S°

Case ∆H° ∆S° ∆G°

I − + −spontaneous at all temperatures ex: 2H 2 O 2 (,) →2H 2 O(,) + O 2 (g)

II + − + nonspontaneous at all temperatures ex: 3O 2 (g) →2O 3 (g)

III + + + nonspontaneous at low temperatures

−spontaneous at high temperatures ex: H 2 (g) + I 2 (g) →2HI(g)

IV −−−spontaneous at low temperatures

+ nonspontaneous at high temperatures ex:

NH 3 (g) + HCl (g) →NH 4 Cl (s)

Part II: Specific Topics