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Chemistry calculators
Start with mass and moles, find a solution concentration, or count the entities in a sample. Each tool keeps the formula, units and working visible.
- MASS ↔ AMOUNT
Grams to moles calculator
Convert mass and moles using a chemical formula or known molar mass. Includes element breakdowns, hydrates, flexible units and batch conversions.
Convert grams and moles - SOLUTION CONCENTRATION
Molarity calculator
Use solute mass, a formula or molar mass, and the final solution volume to find mol/L. See the grams-to-moles step and the concentration calculation.
Calculate solution molarity - MOLECULES, FORMULA UNITS & ATOMS
Grams to molecules calculator
Convert a sample mass into a count with Avogadro’s constant. Explicitly choose molecules, formula units or elemental atoms so the result names what you are counting.
Find an entity count - MASS LOSS → WATER-TO-SALT RATIO
Hydrate formula calculator
Use the anhydrous formula and before-and-after masses to find waters of hydration, with optional container subtraction and no forced whole-number rounding.
Analyze a hydrate ratio - ELEMENTAL COMPOSITION → FORMULA
Empirical formula calculator
Convert elemental masses or percentages to mole ratios. Compare a simple integer candidate with the entered composition and see the fit limits.
Analyze elemental composition - BALANCED REACTION → YIELD & EXCESS
Limiting reactant calculator
Compare two reactant amounts using a balanced equation. Check atom balance, theoretical product yield and leftover excess.
Find limiting reactant and yield - MIXTURE MASSES → MOLE FRACTIONS
Mole fraction calculator
Enter all component masses and formulas to compare mole fractions with mass fractions, with each grams-to-moles step shown.
Calculate mixture mole fractions - MEASURED MASS + P, V, T
Gas molar mass calculator
Estimate molar mass from a gas-only mass, measured volume, absolute pressure and temperature using a confirmed ideal-gas model.
Estimate gas molar mass - SOLUTE MOLES PER SOLVENT MASS
Molality calculator
Calculate molality in mol/kg from solute grams, molar mass and solvent grams. See why solvent mass and total solution volume answer different questions.
Calculate molality - SOLUTION AMOUNT
Molarity to moles calculator
Calculate moles and millimoles of solute from a known molarity and final solution volume. No chemical formula or molar mass is needed for this amount-of-substance calculation.
Find solute moles - EXPERIMENTAL AMOUNT-OF-SUBSTANCE ANALYSIS
Titration molar mass calculator
Find apparent molar mass from sample mass, titrant molarity, equivalence volume and explicit coefficients from a balanced reaction. State the purity and endpoint assumptions.
Calculate apparent molar mass - SOLUTION CONCENTRATION CONVERSION
Mass percent to molarity calculator
Convert mass percent w/w to molarity using the measured density of the whole solution and the solute molar mass. Show grams per liter and millimolar concentration.
Calculate molarity - SINGLE-LIMITING-REACTANT YIELD
Percent yield from reactant grams
Calculate theoretical product grams and percent yield from one known limiting reactant, its molar mass, balanced-equation coefficients, product molar mass and actual product mass.
Calculate observed yield - COMBINED SOLUTE INVENTORY
Mix two solutions molarity calculator
Combine two solutions of the same solute with known molarities and volumes, then estimate final molarity and total solute mass with an explicit final-volume assumption.
Calculate mixture molarity - COMPOSITION AND MOLAR-MASS COMPARISON
Molecular formula from empirical formula calculator
Turn an empirical formula and independently measured molar mass into a molecular formula when their mass ratio is close to a whole number.
Multiply empirical subscripts
Useful chemistry tools, free to reuse. If a calculation needs a correction or a clearer explanation, email contact@gramstomoles.org.