This all-in-one online Molarity Calculator performs calculations using the formula linking the molarity of a solution for a compound of known molecular weight with the mass of the compound and the volume of the solution.
Molarity Formula
Molarity or molar concentration is the number of moles of solute per liter of solution. A solution with a concentration of 1 mol/L is said to be 1 molar, commonly designated as 1 M.
Our molarity calculator is based on the following formula:
Mass (g) = Concentration (mol/L) x Volume (L) x Molecular Weight (g/mol).
With the help of our handy tool you can easily calculate:
• mass of a compound required to prepare a solution of known volume and concentration,
• concentration of a solution resulting from a known mass of compound in a specific volume,
• volume of solution obtained when dissolving a compound of known mass to a desired concentration,
• molecular weight of a compound given its mass as well as the molarity and volume of the solution.
Molarity is a useful concept for stoichiometric calculations involving reactions in solution, such as, for example, precipitation and neutralization reactions.
Making a Solution with a Specific Concentration
Let’s consider an example. Suppose we want to make 250 mL of an aqueous solution of NaCl with molar concentration 0.75 M. What mass of the solute NaCl would we need to make this solution?
We are given the volume and concentration of the desired solution. We only need to know the molecular weight of NaCl. Using our molecular weight calculator we can easily get its value: 58.4428 g/mol. Now, plugging all the numbers into the calculator we have: 10.95802 g of NaCl.
In practice, we could use this information to make our solution as follows:
1. Weigh out 10.96 g of sodium chloride.
2. Add some water to the NaCl and stir until the NaCl is completely dissolved. Add more water until the total volume of the solution is 250 mL.
Related calculators
Check out our other chemistry calculators such as Chemical Equation Balancer Calculator or Stoichiometry Calculator.