Chemistry

Mole

n = mass / molar mass = particles / 6.022 × 10²³

Avogadro number

Molarity

M = moles of solute / litres of solution

pH

pH = −log[H⁺]

< 7 acidic, 7 neutral, > 7 basic

Ideal gas

PV = nRT

R = 8.314 J/mol K

Common names

NaCl salt · NaHCO₃ baking soda · Na₂CO₃·10H₂O washing soda · CaOCl₂ bleaching powder

More common names

CaSO₄·½H₂O plaster of Paris · CaCO₃ limestone · CaO quicklime · Ca(OH)₂ slaked lime

Acids in daily life

Vinegar – acetic · Lemon – citric · Curd – lactic · Ant sting – formic (methanoic)

Boyle's law

P₁V₁ = P₂V₂

At constant temperature

Charles's law

V₁/T₁ = V₂/T₂

T in kelvin, constant pressure

Mass number

A = Z + N

Z = protons, N = neutrons

Percentage composition

% = (mass of element / molar mass) × 100