Science calculators
Chemistry helpers such as molar mass with a per-element breakdown and mass percent composition.
Science guides
Molar Mass vs. Molecular Weight vs. Formula Mass: What's the Difference?Clear definitions of molar mass, molecular weight, formula mass and atomic mass units, why their numbers match, and how to calculate each from a chemical formula.
Grams to Moles and Moles to Grams: Conversions with Worked ExamplesConvert between grams, moles and number of particles using molar mass and Avogadro's number, with step-by-step examples and a stoichiometry walkthrough.
Percent Composition by Mass: How to Calculate It and Why It MattersCalculate the mass percent of each element in a compound from its formula, check the result, and use percent composition in labs, nutrition labels and fertilizers.
Molarity and Preparing Solutions: From Molar Mass to Grams to WeighCalculate how many grams to weigh for a solution of a given molarity, dilute stock solutions with C1V1 = C2V2, and avoid common preparation mistakes.
Molar Mass of Hydrates: Formulas, Calculations and the Classic Heating LabHow to read hydrate formulas like CuSO4·5H2O, calculate their molar mass and percent water, and find the formula of an unknown hydrate from lab data.
Empirical and Molecular Formulas: From Percent Composition to the Real FormulaFind an empirical formula from percent composition or masses, then use molar mass to get the molecular formula. Worked examples with every step.