About Molarity Calculator (Mass to Concentration)

What is Molarity?

Molarity is a measure of the concentration of a solution, defined as the number of moles of solute per liter of solution. It is one of the most commonly used expressions of concentration in chemistry.

Formula and Meaning

The formula for molarity is:

\[ Molarity (M) = \frac{moles\,of\,solute}{liters\,of\,solution} \]

Where:

• Molarity is expressed in moles per liter (mol/L or M)
• Moles of solute is the amount of dissolved substance
• Liters of solution is the total volume of the solution

Calculation Steps

To calculate molarity from mass:

1. Calculate the number of moles of solute: \[ moles = \frac{mass\,of\,solute}{molar\,mass\,of\,solute} \]
2. Divide the moles of solute by the volume of the solution in liters: \[ Molarity = \frac{moles\,of\,solute}{volume\,of\,solution\,(L)} \]

Example and Visual Representation

Let's calculate the molarity of a solution made by dissolving 5.85 g of NaCl in 500 mL of water:

Steps:

1. Calculate moles of NaCl: \[ moles = \frac{5.85\,g}{58.44\,g/mol} = 0.1\,mol \]
2. Calculate molarity: \[ Molarity = \frac{0.1\,mol}{0.5\,L} = 0.2\,M \]

This example demonstrates how to calculate molarity from mass and volume, showing the relationship between the amount of solute and the concentration of the solution.