Chemistry Formula Sheet
22 formulas across 4 chapters — with variables explained and exam tips where needed.
Ch 1Solutions(9 formulas)
Molarity
mol/LM = (moles of solute) / (volume of solution in L)
Molality
mol/kgm = (moles of solute) / (mass of solvent in kg)
Mole fraction
χ_A = n_A / (n_A + n_B)
Mass percentage
w/w% = (mass of solute / mass of solution) × 100
Raoult's Law
p_A = χ_A × p°_A
For ideal solutions
Elevation in boiling point
ΔT_b = K_b × m
K_b = ebullioscopic constant, m = molality
Depression in freezing point
ΔT_f = K_f × m
K_f = cryoscopic constant
Osmotic pressure
π = CRT = (n/V)RT
R = 0.0821 L·atm/mol·K
van't Hoff factor
i = observed colligative property / calculated value (assuming no association/dissociation)
Ch 2Electrochemistry(7 formulas)
Nernst Equation
E_cell = E°_cell − (0.0592/n) log Q (at 25°C)
n = moles of electrons, Q = reaction quotient
Gibbs free energy and EMF
ΔG° = −nFE°_cell
F = 96485 C/mol (Faraday constant)
Faraday's First Law
m = ZIt = (M/nF)It
Z = electrochemical equivalent, I = current, t = time
Conductance
S (Siemens)G = 1/R = κ × A/l
Molar conductivity
S·cm²/molΛ_m = κ × 1000/C
C = concentration in mol/L
Kohlrausch's Law
Λ°_m = ν₊λ°₊ + ν₋λ°₋
Relation between ΔG and K
ΔG° = −RT lnK = −nFE°_cell
Ch 3Chemical Kinetics(5 formulas)
Rate of reaction
rate = −(1/a) d[A]/dt = k[A]ⁿ[B]ᵐ
Overall order = n + m
First order rate constant
s⁻¹k = (2.303/t) log([A]₀/[A])
Half-life (first order)
t₁/₂ = 0.693/k
Independent of initial concentration
Arrhenius Equation
k = Ae^(−Ea/RT)
Ea = activation energy, A = frequency factor, R = 8.314 J/mol·K
Arrhenius (log form)
log(k₂/k₁) = (Ea/2.303R)(1/T₁ − 1/T₂)
Ch 4Surface Chemistry(1 formulas)
Freundlich Adsorption Isotherm
x/m = kp^(1/n)
log(x/m) = log k + (1/n) log p — used for graph questions