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Chemicals – Technical Library

Mass Molarity Calculator

 Calculate Mass Required for Molar Solution

    Formula weight: g/mol

    Desired final volume:

    Desired concentration:


The mass molarity calculator tool calculates the mass of compound required to achieve a specific molar concentration and volume. To dilute a solution of known molarity, please use the Solution Dilution Calculator.  To dilute a solution of concentrated acid or base of known w/w% strength, please use the Acid & Base Molarity Calculator.

How to calculate mass

Mass (m) is the amount of matter present in a substance. The value is constant and, unlike weight, is not affected by gravity.

Mass, molar concentration, volume, and formula weight are related to each other as follows:

Mass (g) = Concentration (mol/L) * Volume (L) * Formula Weight (g/mol)

Formula weight (F.W.) is the sum of the atomic weights of all atoms in a given empirical formula. For example: Sodium chloride (NaCl) has one atom of sodium (Na) and one atom of chlorine (Cl). The atomic weight of sodium is 22.99 g/mol and chlorine is 35.45 g/mol. Therefore, the formula weight of NaCl is 58.44 g/mol (22.99 g/mol + 35.45 g/mol).

Molar concentration is the amount of a solute present in one unit of a solution. Its units are mol/L, mol/dm3, or mol/m3. “Molar concentration” is also known as “molarity” and can be denoted by the unit M, molar. If we want to prepare 1 L of 0.5 M sodium chloride solution, then as per the formula we require 29.22 g of sodium chloride (0.5 mol/L * 1L * 58.44 g/mol = 29.22 g).

Molarity App from Sigma-Aldrich 
for iPhone, iPod touch, and iPad 
Download App from iTunes