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Chemistry Formula Sheet

All important Chemistry formulas for Class 6–12, grouped chapter-wise for fast, exam-ready revision.

Atoms & Molecules

Number of neutrons
n = A − Z
Maximum electrons in a shell
electrons = 2n2
Molecular mass
sum of atomic masses of all atoms in the molecule
Atomic number
Z = number of protons = number of electrons (neutral atom)

Mole Concept & Stoichiometry

Moles from mass
n = given mass / molar mass
Moles from particles
n = N / NA
Avogadro's number
NA = 6.022 × 1023 mol−1
Moles of a gas at STP
n = volume at STP / 22.4 L
Number of particles
N = n × NA

Concentration of Solutions

Molarity
M = moles of solute / volume of solution (L)
Molality
m = moles of solute / mass of solvent (kg)
Mass percentage
% = (mass of solute / mass of solution) × 100
Mole fraction
xA = nA / (nA + nB)
Parts per million
ppm = (mass of solute / mass of solution) × 106
Dilution
M₁V₁ = M₂V₂
Normality
N = gram equivalents of solute / volume of solution (L)

Gas Laws

Boyle's law
P₁V₁ = P₂V₂ (T constant)
Charles' law
V₁/T₁ = V₂/T₂ (P constant)
Gay-Lussac's law
P₁/T₁ = P₂/T₂ (V constant)
Combined gas law
P₁V₁/T₁ = P₂V₂/T₂
Ideal gas equation
PV = nRT
Gas constant
R = 0.0821 L·atm·K−1·mol−1
Dalton's law
Ptotal = P₁ + P₂ + P₃ …

Atomic Structure

Energy of a photon
E = h·ν = h·c / λ
de Broglie wavelength
λ = h / (m·v)
Bohr — energy of nth orbit
Eₙ = −13.6 / n2 eV (for H atom)
Number of orbitals
number of orbitals in a shell = n2
Maximum electrons
electrons in a shell = 2n2

Thermodynamics

First law
ΔU = q + w
Enthalpy change
ΔH = Hproducts − Hreactants
Enthalpy & internal energy
ΔH = ΔU + ΔnRT
Gibbs free energy
ΔG = ΔH − TΔS
Spontaneity
ΔG < 0 spontaneous, ΔG > 0 non-spontaneous

Chemical Equilibrium

Equilibrium constant
Kc = [products] / [reactants]
Kp and Kc relation
Kp = Kc(RT)Δn
Reaction quotient
Q = [products] / [reactants] at any instant
Gibbs energy & K
ΔG° = − RT ln K

Ionic Equilibrium (Acids & Bases)

pH
pH = −log[H+]
pOH
pOH = −log[OH−]
pH + pOH
pH + pOH = 14 (at 25°C)
Ionic product of water
Kw = [H+][OH−] = 10−14
Acid dissociation
pKa = −log Ka

Redox & Electrochemistry

Cell potential
E°cell = E°cathode − E°anode
Nernst equation
E = E° − (0.0591/n)·log Q (at 298 K)
Gibbs energy & emf
ΔG° = − nFE°cell
Faraday's law
mass deposited m = (Z·I·t), Z = E / F
Conductivity
κ = (1/R)·(l/A)

Chemical Kinetics & Solutions

Rate of reaction
rate = − Δ[reactant]/Δt = Δ[product]/Δt
First-order rate
k = (2.303/t)·log([A₀]/[A])
Half-life (first order)
t½ = 0.693 / k
Arrhenius equation
k = A·e(−Ea/RT)
Raoult’s law
psolution = xsolvent · p°solvent
Elevation in boiling point
ΔTb = Kb · m
Depression in freezing point
ΔTf = Kf · m
About this sheet

About the Chemistry Formula Sheet

This Chemistry formula sheet gathers the most important formulas, relations and constants from Class 6 to Class 12 in a single page. It covers the basics of atoms and molecules from Class 9, the mole concept and chemical reactions from Class 10 and 11, and the quantitative topics of thermodynamics, equilibrium, electrochemistry and chemical kinetics from Class 11 and 12.

All formulas are aligned to the NCERT / CBSE syllabus and are equally helpful for ICSE, State Board and NEET / JEE aspirants. Physical Chemistry is highly formula-driven, so keeping these relations at your fingertips makes solving numericals far faster during revision and exams.

  • Mole concept, stoichiometry and Avogadro's number
  • Molarity, molality, mole fraction and other concentration terms
  • Gas laws and the ideal gas equation
  • Atomic structure and Bohr's model relations
  • Thermodynamics, equilibrium and ionic equilibrium (pH)
  • Redox, electrochemistry, kinetics and colligative properties
FAQ

Chemistry Formulas — FAQs

Quick answers about using this Chemistry formula sheet for Class 6–12 revision.

Yes. The Class 10 foundations — atoms and molecules, molecular mass and the basics of the mole concept used in chemical reactions — are included along with their key relations.
Physical Chemistry is the most formula-driven part: mole concept, gas laws, thermodynamics, equilibrium, electrochemistry, chemical kinetics and solutions all rely heavily on the formulas in this sheet.
Yes. The Physical Chemistry formulas listed here are directly used in NEET and JEE numerical problems, so they are an excellent quick-revision resource.
R = 0.0821 L·atm·K⁻¹·mol⁻¹ in the ideal gas equation PV = nRT, and 8.314 J·K⁻¹·mol⁻¹ when energy is expressed in joules.

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