🧪 Chemistry

5 sub-categories in this category.

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Chemistry calculators for the mole concept, solutions, gas laws, acids and bases, chemical kinetics and thermodynamics. Each one shows the formula, explains the symbols and units, and includes worked examples.

They follow the methods taught in CBSE/NCERT Class 11–12, IGCSE, IB and A-level chemistry. The molar mass calculator reads any chemical formula, including brackets and hydrates.

Sub-categories

Moles & Stoichiometry

Solutions & Concentration

Acids, Bases & pH

Kinetics & Thermochemistry

⚖️ Moles & Stoichiometry

Type a chemical formula such as H2SO4, Ca(OH)2 or CuSO4·5H2O to get its molar mass in g/mol and the percent composition of each element. Optionally convert grams to moles.

Grams ↔ Moles

Convert grams to moles and moles to grams with n = m ÷ M, and get the number of particles with Avogadro's number and the volume of a gas at STP.

Calculate the percentage yield of a reaction from the actual yield and the theoretical yield: % yield = actual ÷ theoretical × 100.

💧 Solutions & Concentration

Calculate the molarity of a solution from the mass of solute, its molar mass and the volume, or find the mass needed to make a solution of a given molarity.

Dilution (C₁V₁ = C₂V₂)

Use the dilution equation C₁V₁ = C₂V₂ to find the volume of stock solution needed, the final concentration or the final volume, and how much solvent to add.

Calculate molality (mol per kg of solvent) from the mass of solute, its molar mass and the mass of solvent, plus the freezing point depression and boiling point elevation in water.

Calculate the concentration of a solution as mass percent (w/w), mass fraction, parts per million (ppm) and parts per billion from the mass of solute and solvent.

Calculate the mole fraction of each component in a two-component mixture from their masses and molar masses, plus their mole percentages.

🎈 Gas Laws

Solve the ideal gas equation PV = nRT for pressure, volume, moles or temperature. Pressure in atm, volume in litres, temperature in kelvin or °C.

Use Boyle's law P₁V₁ = P₂V₂ to find the new volume or new pressure of a gas at constant temperature.

Use Charles's law V₁/T₁ = V₂/T₂ to find the new volume of a gas when its temperature changes at constant pressure. Temperatures in °C are converted to kelvin.

Combined Gas Law

Use the combined gas law P₁V₁/T₁ = P₂V₂/T₂ to find the new volume of a gas when both pressure and temperature change. Temperatures in °C are converted to kelvin.

🍋 Acids, Bases & pH

Calculate pH, pOH, hydrogen ion concentration [H⁺] and hydroxide ion concentration [OH⁻] from any one of them, at 25 °C.

Calculate the pH of a buffer solution with the Henderson–Hasselbalch equation pH = pKa + log([A⁻]/[HA]). Enter pKa or Ka and the concentrations of the salt and acid.

⏱️ Kinetics & Thermochemistry

Calculate how much of a radioactive substance (or first-order reactant) remains after a given time from its half-life: N = N₀ × (½)^(t/t½). Also gives the decay constant.

First Order Rate Constant

Calculate the rate constant k of a first-order reaction from the initial and remaining concentration and the time, k = (2.303/t) log([A]₀/[A]), plus the half-life.

Arrhenius Equation

Use the Arrhenius equation to find the rate constant at a new temperature from the rate constant at one temperature and the activation energy: log(k₂/k₁) = Ea/2.303R (1/T₁ − 1/T₂).

Gibbs Free Energy

Calculate the Gibbs free energy change ΔG = ΔH − TΔS to see whether a reaction is spontaneous, plus the equilibrium constant K from ΔG° = −RT ln K.