Chemistry Formula Sheet

Chemistry formula sheet

This chemistry formula sheet (also an equation sheet for general and AP chemistry) collects the relations you actually type into homework: moles, dilution, equilibrium, Ksp, pH, gases, rates, and heat. Each block links to a calculator on this site so you can check a number after you write the equation.

Moles, mass, and particles

n = m / M
N = n × Nₐ    Nₐ = 6.02214076×10²³ mol⁻¹
% mass(i) = (nᵢ Aᵢ / M) × 100%

Use the Stoichiometry Calculator for molar mass and the Composition & Empirical Formula Calculator for percent composition.

Balanced equations and limiting reagent

mole ratio from coefficients
n_product = n_limiting × (coeff_product / coeff_limiting)
theoretical yield (g) = n_product × M_product
percent yield = (actual / theoretical) × 100%

Balance first with the Chemical Equation Balancer, then find the limiting reagent with the Limiting Reagent Calculator. Redox in acid or base: Redox Equation Balancer.

Dilution and concentration

C₁V₁ = C₂V₂
dilution factor = C₁ / C₂ = V₂ / V₁
M = mol / L     mM = 10⁻³ M     μM = 10⁻⁶ M
% w/v = (g solute / 100 mL) × 100

Dilution Calculator for C₁V₁ and serial dilutions; Molarity & Concentration Converter for M, mg/mL, ng/mL, % w/v, and ppm.

Equilibrium (Kc, Kp, Q)

Kc = Π [products]^ν / Π [reactants]^ν
Kp = Kc (RT)^{Δn}
Q uses the same form with current amounts
Q < K forward; Q > K reverse; Q = K at equilibrium

ICE tables and Kc/Kp: Chemical Equilibrium Calculator.

Ksp and precipitation

AB:    Ksp = s²
AB₂:   Ksp = 4s³
A₃B₂:  Ksp = 108 s⁵
Q > Ksp → precipitate expected

Ksp Calculator converts s ↔ Ksp and compares Q with Ksp (BaCrO₄, A₃B₂ homework chips included).

pH, pOH, and buffers

pH = −log₁₀[H⁺]     pOH = −log₁₀[OH⁻]     pH + pOH = 14 (25 °C)
weak acid: [H⁺] ≈ √(Ka C)
Henderson–Hasselbalch: pH = pKa + log₁₀([A⁻]/[HA])

pH Calculator for strong/weak acids and neutralization; Phosphate Buffer Calculator for named recipes and McIlvaine citrate–phosphate.

Ideal gas law

PV = nRT
R = 0.082057 L·atm/(mol·K)
T(K) = t(°C) + 273.15
M = dRT / P   (d in g/L)

Ideal Gas Law Calculator.

Kinetics (integrated rate laws)

zero order:  [A] = [A]₀ − kt      t½ = [A]₀ / (2k)
first order: ln[A] = ln[A]₀ − kt  t½ = ln 2 / k
second order: 1/[A] = 1/[A]₀ + kt t½ = 1 / (k [A]₀)

Kinetics Calculator.

Thermochemistry and Nernst

ΔH°rxn = Σ ν ΔH°f(products) − Σ ν ΔH°f(reactants)
q = m c ΔT
E = E° − (RT/nF) ln Q
ΔG = −n F E

Thermochemistry Calculator and Nernst Equation Calculator.

Browse every chemistry tool on the chemistry calculators page.