Enter the mass of solute, its molar mass, and the total solution volume to calculate the number of moles and the resulting molarity of the solution.
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Molarity (concentration) is calculated in two steps: first, moles of solute = mass (g) ÷ molar mass (g/mol). Then, molarity (mol/L) = moles of solute ÷ solution volume (L). Molar mass is specific to each compound, for table salt (NaCl) it's about 58.44 g/mol, found by summing the atomic masses of all atoms in the formula.
Dissolving 58.44 g of NaCl (1 mole) into a total solution volume of 1 liter gives a 1 mol/L (1 M) solution, a standard reference concentration used throughout chemistry.
Using the volume of solvent added instead of the total final solution volume, dissolving a solid changes the total volume somewhat, molarity is defined using the final solution volume after mixing, not just how much water you started with.
Looking up the wrong molar mass for a hydrated compound, many lab reagents are hydrates (like CuSO₄·5H₂O), which have a meaningfully higher molar mass than the anhydrous form, using the wrong one skews the resulting molarity.
Mixing up mass and moles when reading a recipe or procedure, this calculator takes mass in grams as input and converts to moles internally, entering a moles value directly into the mass field would give a nonsensical result.
Add up the atomic masses (from the periodic table) of every atom in the compound's chemical formula. Many reference sites and chemistry textbooks also list molar masses directly for common compounds.
No, it means the total final volume of the solution after the solute is fully dissolved, not just the volume of solvent used, this is an important distinction in accurate lab work.
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