How this calculation works
The Molarity & Solution Concentration Calculator computes solution molarity (M in moles per liter), total moles of solute, and millimolar (mM) concentrations for chemical laboratory preparation.
Mathematical formula and logic
Moles = Mass (g) / Molar Mass (g/mol). Molarity (M) = Moles / Volume (Liters). Millimolarity (mM) = Molarity × 1,000.
Worked example
Dissolving 58.44 grams of Sodium Chloride (NaCl, molar mass 58.44 g/mol) in 1.0 Liter of water yields 1.00 Molar (1.00 M = 1,000 mM) saline solution.
Calculation assumptions
- IUPAC standard atomic weight definitions.
- Homogeneous solution volume measured in Liters at standard temperature (20°C).
Frequently asked questions
What is Molarity (M)?
Molarity is the most common measure of chemical concentration in laboratories, defined as the number of moles of solute dissolved per liter of solution (mol/L).
What is the difference between Molarity and Molality?
Molarity (M) is moles of solute per *liter of solution* (temperature-dependent due to thermal liquid expansion). Molality (m) is moles of solute per *kilogram of solvent* (temperature-independent).
How do I calculate the grams needed to make a specific molarity solution?
Mass in Grams = Desired Molarity (M) × Volume (L) × Molar Mass (g/mol).
What is 1 millimolar (mM)?
One millimolar (1 mM) equals 0.001 Moles per liter (10⁻³ M), widely used in biochemistry and cell culture reagents.
Does adding solute increase the total liquid volume?
Yes, when preparing molar solutions, dissolve the solute in a portion of solvent first, then top up with solvent to the exact target volumetric flask mark (q.s. to volume).