Substances can exist in various forms, like elements, compounds, ion complexes, and so on. Each of these forms contain different number of particles. For example, the number of particles in 1 gram of common salt (sodium chloride) is different from that in 1 gram of baking soda (sodium bicarbonate). Moreover, because atoms and molecules are so small, they cannot be spotted by the naked eye, as even a small amount can contain billions of them. But, the knowledge of the number of particles is essential to understand the correct proportion of chemicals used in industrial processes. To make this easier, the concept of a mole was introduced. A mole is an amount of a substance which contains the same number of particles as the number of atoms in 12 grams of the C-12 isotope of carbon. This number, called the Avogadro Constant, is 6.022 × 10²³. Therefore, 1 mole of any substance, whether salt or baking soda, contains an equal number, of 6.022 × 10²³ molecules. So, the concept of a mole relates the amount of a substance with the number of particles it will contain. But, this only gives the number of particles, not the weight. In this context, the concept of molar mass finds relevance. It is the weight of one mole of a substance. Let us understand what the steps are to find the molar mass of methanol (CH₃OH), considering that it is a common solvent used in chemical manufacture, and an alternative fuel. There is often a lot of confusion between molecular mass and molar mass. Since molecular mass deals with the weight of one molecule of a substance, it remains constant and has no units. Molar mass, on the other hand, changes with the number of moles, and is expressed in g/mol or kg/mol. So, the molar mass of 1 mole of methanol is 32.04 g/mol, that of 2 moles is 62.04 g/mol, and so on. However, the molar mass of 1 mole and the molecular mass are numerically similar.