Chemistry calculator
Solution Preparation Calculator
Calculate the solid solute mass needed to prepare a molar solution.
Required solute mass
7.305 g
How the solution preparation calculator works
Desired molarity multiplied by final liters gives required moles. Multiplying those moles by the solute’s molar mass gives grams to weigh.
This models preparation from a solid: dissolve the measured solute, then bring the mixture to the stated final volume. It is not a stock-solution dilution calculation.
Worked example
To prepare 250 mL of 0.500 M NaCl using 58.44 g/mol: 250 mL = 0.250 L, moles = 0.500×0.250 = 0.125 mol, and mass = 0.125×58.44 = 7.305 g.
Assumptions and practical limits
Final volume is the completed solution volume, not the volume of solvent initially poured. Use volumetric glassware when accuracy matters.
Purity, hydrates, assay values, density changes, and weighing uncertainty are not corrected. Adjust mass separately when reagent purity is below 100%.
Frequently asked questions
Is this the same as dilution?
No. It calculates solid mass; dilution starts from an existing stock concentration.
Why convert milliliters to liters?
Molarity is moles per liter, so milliliters are divided by 1,000.
Do I add exactly 250 mL of water?
No. Dissolve the solute and bring the complete solution to 250 mL final volume.