Molarity is a term used often in chemistry. But if you’re new to the field, you might be confused as to what molarity and moles are. In this post, we’re going to go over what they mean, and how to calculate them, so keep reading!

What is molarity?

Molarity is the number of moles of solute per liter of solution. It’s expressed in moles per liter, or mol/L.

A common way to think about molarity is that it’s like density: the more stuff you have packed inside something (say, a jar), the higher its density will be. In this case, “more” means more particles instead of more space between them (which would increase volume). This means that if we want to measure how many molecules are packed into every cubic meter of solvent (or any other type of solution), we can just put some stuff into a jar full of solvent and count how many molecules we get when we stir it up!

Mole (mol)

The mole is the SI base unit of the amount of substance. The name comes from the Greek word μολος, which means a small portion or morsel.

The mole is the amount of a substance that contains as many elementary entities as there are atoms in 12 grams of carbon-12 (12C). It was adopted by an international agreement in 1971 and defined as “the number of entities equal to one mole” (symbol mol). This definition is equivalent to Avogadro’s number, which has been used since about 1811 for this purpose.

Avogadro’s constant

Avogadro’s constant, named after Amedeo Avogadro, is a physical constant that is the number of atoms in 12 grams of carbon-12, the most common isotope of carbon. Avogadro’s number, NA, has a value of 6.022140857×1023 mol−1.

How to use the molarity calculator

Essentially, you’re going to use this calculator to convert grams per milliliter to moles. In order to do that, however, you need to know a few things:

  • The molar mass – you can calculate it by adding up the molar masses of the elements that make up the compound
  • Concentration – how much of a mixture is the constituent

As well as that, if you know the mass. you can calculate the overall volume of the solution.


What is molar concentration?

Molar concentration is a measure of the concentration of a chemical species, in particular of a solute in a solution

What is the unit for molar concentration?

Molar concentration is expressed in moles per liter (or milliliter).

When did we start using moles?

The term “mole” was adopted by an international agreement in 1971 and defined as “the number of entities equal to one mole” (symbol mol).