Solution preparation
Molarity Calculator
Free molarity calculator for solution preparation. Calculate grams of reagent, molar concentration, or final volume from molar mass and target concentration.
Solve for
Your prep amounts will appear here
mass = conc × volume × MWmass (g) = conc (mol/L) × volume (L) × MW (g/mol)Example: prepare 100 mL of 1 M NaCl
- 1Set target concentration to 1 M.
- 2Set target volume to 100 mL.
- 3Enter NaCl molar mass: 58.44 g/mol.
- 4The required mass is 5.844 g NaCl, then bring to 100 mL final volume.
Common mistakes to avoid
- Using milliliters as liters without conversion.
- Ignoring reagent purity when preparing analytical standards.
- Adding a fixed solvent volume instead of bringing the solution to final volume.
Frequently asked questions
How do I calculate grams from molarity?
Convert final volume to liters, multiply by target molarity, then multiply by molar mass in g/mol. The result is grams of solute.
Can LabTools solve for concentration instead of mass?
Yes. The reagent prep tool can solve for mass, concentration, or final volume depending on which value you need.
Should purity be included in molarity calculations?
For high-accuracy analytical work, yes. If a reagent is less than 100% pure, account for purity or use a certified standard.
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