Molarity is calculated by dividing the number of moles of solute by the volume of the solution in litres.

Molarity, commonly represented by the symbol $M$, is a quantitative measure of the concentration of a solute within a solution. It is defined as the number of moles of solute per litre of solution. To calculate molarity, you need two key pieces of information: the number of moles of solute and the total volume of the solution.

The formula for calculating molarity is given by:

To apply this formula, you must first determine the number of moles of the solute. This can be accomplished using the following equation:

In this equation, the mass refers to the weight of the solute in grams, while the molar mass denotes the weight of one mole of the solute, also expressed in grams. You can find the molar mass of each element on the periodic table.

Once you have calculated the number of moles, you can then determine the molarity. For instance, if you have $0.5$ moles of solute dissolved in $2$ litres of solution, the molarity would be calculated as follows:

It is important to remember that the volume of the solution refers to the total volume of the solution itself, not merely the volume of the solvent. For example, if you dissolve a solute in water to achieve a total volume of $1$ litre of solution, the volume of the solution is indeed $1$ litre, rather than just the volume of the water used.

In summary, molarity serves as a valuable measure of concentration in the field of chemistry. It is calculated by dividing the number of moles of solute by the volume of the solution in litres.