The formula for molarity is given by

$M = \frac{n}{V}$

where $M$ represents molarity, $n$ is the number of moles of solute, and $V$ is the volume of the solution expressed in liters.

Molarity is a quantitative measure of the concentration of a solute within a solution, specifically reflecting the amount of a chemical species per unit volume. It is defined as the ratio of the number of moles of solute ($n$) to the volume of the solution ($V$). The unit of molarity is moles per liter, commonly abbreviated as $M$.

To calculate molarity, you first need to determine the number of moles of the solute. This can be achieved by dividing the mass of the solute by its molar mass. The molar mass corresponds to the mass of one mole of a substance, which can be found on the periodic table for elements or calculated for compounds by summing the molar masses of their constituent elements.

Next, measure the volume of the solution, typically in liters. If the volume is provided in a different unit, such as milliliters, you can convert it to liters by dividing by $1000$ (since $1 \text{ L} = 1000 \text{ mL}$).

Finally, to find the molarity, divide the number of moles of solute by the volume of the solution in liters:

$M = \frac{n}{V}$

This calculation yields the concentration of the solute in the solution, expressed in moles per liter.

It is important to remember that molarity serves as a crucial method for expressing concentration. It indicates how much of a specific substance exists within a defined volume of solution. This measurement is especially valuable in chemistry when dealing with reactions in solution, as it facilitates the calculation of the amounts of reactants and products involved.