# How do I calculate concentration from density?

#### Posted August 23, 2023

Answer

The first step is to divide the solute’s mass by its molar mass. For example, if the solution has 20 grams of sodium chloride, (which has a molar mass of 58.44 mg/mol), 20 / 58.44 = 0.342 moles.

Then, the mass of the solute must be added to the mass of the solute. If the sodium chloride is dissolved in 50 grams of water, 20 + 50 = 80.

Next, this sum should be divided by the solution’s density. If the density is 1.53 grams per cubic cm: 80 / 1.53 = 52.29 cm^3. This answer is the solution’s volume.

Next, in order to convert to liters, the volume must be divided by 1,000.

52.29 / 1000 = 0.052.

The last step is to divide the answer from step 1 (0.342) by the answer to step 4 (0.052).

0.342 / 0.052 = 6.58 moles per liter.

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