Chem 102H - Spring 2016
Equations You Should Know
Gases
Ideal Gas Law
PV = nRT
Thermodynamics
Pressure-Volume Work
w = !PÄV
(w = P-V work)
First Law
ÄU = q + w
(U = internal energy, q =
heat, w = work)
Enthalpy
ÄH = ÄU + PÄV
(H = enthalpy; at
constant P, q = H)
Second Law
ÄS =
(S = entropy)
Heat Capacities
ÄU = nCv ÄT
(Cv = heat capacity at
constant volume)
ÄH = nCp ÄT
(Cp = heat capacity at
constant pressure)
ÄG = ÄH ! TÄS
(G = Gibbs energy; constant
T and P)
Gibbs Energy
Equilibrium
Equilibrium Constant
For the reaction: aA + bB W cC + dD
(Än = change in number of
moles of gas during rexn.)
Relationship of K to Gibbs Energy:
ÄGE = !RT ln K p
Acids, Bases and Solution Equilibria
Autoionization of Water
Kw = [H3O+] [OH!] = 1 x 10!14
pH Scale
Weak Acids and Bases
For:
HA (aq) + H2O (l) W H3O+ (aq) + A! (aq)
For:
B (aq) + H2O (l) W HB+ (aq) + OH! (aq)
Buffer Solutions
Solubility Product
(weak acid/conjugate base buffers)
For dissolution reaction: AxBy (s) W xAm+ (aq) + yBn! (aq)
Ksp = [Am+]x[Bn-]y
Electrochemistry
Free Energy
ÄGE = !nFEE
and
ÄG = !nFE
(where F = Faraday’s Constant = 96,485 C/mol e!’s)
Faraday’s Laws
Nernst Equation
At 25EC,
Kinetics
Rate Laws
Arrhenius Equation
For reaction: aA + bB + ... 6 Products