 # Mole in chemistry: What is it and how to calculate it?

In 1811, Italian physicist Amedeo Avogadro proposed the concept of the mole. Avogadro suggested that equal volumes of different gases, at the same pressure and temperature, contain the same number of molecules. This proposal became known as Avogadro’s Law.

The term “mole” was first applied to a specific number of atoms by German chemist Johann Josef Loschmidt about 50 years after Amedeo Avogadro proposed the concept. In 1865, he estimated that roughly 6.02 × 1023 atoms were in one cubic centimeter of air at standard temperature and pressure. Other scientists later confirmed this value, which became known as Loschimdt’s number or Avogadro’s constant.

The 6.02 × 1023 particles of atoms, molecules, or formula units are called Avogadro’s constant, which is equal to one “mole” of the respective substance. In simple words, one mole is equivalent to 6.02 × 1023 particles, similar to how a dozen eggs equate to 12 eggs.

In this article, we are going to discuss the mole, its formula, and its calculation.

## What is the Mole in Chemistry?

A mole is a unit of measurement in chemistry, which represents the amount of a substance that contains 6.02 × 1023 particles (atoms, molecules, or formula units). It creates a link between the mass of a substance and the number of particles it contains. The abbreviated term for a mole is “mol“.

As we know that a substance may be an element or compound. The mass of a substance is one of the following: atomic mass, molecular mass, or formula mass. These masses are expressed in atomic unit mass (amu). However, if these masses are represented in grams, then they are called molar masses. Molar mass is measured in grams per mole (g/mole).

In simple words, the molar mass of a substance, represented in grams, is numerically equivalent to the mass of one mole of that substance. For example, the molar mass of carbon-12 is exactly 12 grams per mole, which means that one mole of carb-12 atoms has a mass of 12 grams. This relationship helps chemists relate a substance’s mass to the number of moles using the molar mass as a conversion factor.

In simple words, the molar mass of a substance, represented in grams, is numerically equivalent to the mass of one mole of that substance. For example, the molar mass of carbon-12 is exactly 12 grams per mole, which means that one mole of carb-12 atoms has a mass of 12 grams. This relationship helps chemists relate a substance’s mass to the number of moles using the molar mass as a conversion factor.

## Mole related Formulas

We calculate the number of moles from a given mass by using the following equation:

Number of the moles = Mass of a substance / molar mass of the substance

When we rearrange the above equation to calculate the mass of a substance from the number of moles, we get,

Mass of substance = number of moles × molar mass

Also,

Molar mass = Mass of substance/number of mole

The number of particles can find out from the calculated number of moles by the following equation:

Number of the particles = number of the moles × 6.02 × 1023

## How to calculate the mole of a substance?

Follow the following steps to determine the mole of a substance.

·       If the mass of the substance is given, go to the next steps; if not, you can measure the mass using a balance.

·       The molar mass refers to the mass of one mole of a substance and it is expressed in grams per mole. It can be obtained from the periodic table or by adding the atomic masses of all the atoms in molecules.

·       If we have the mass and molar mass of the substance, we can obtain a mole of the substance By dividing the mass of the substance by molar mass.

The number of moles = Mass of a substance / molar mass of the substance

A moles calculator is a best way to calculate the mole of a substance according to the above formula with steps in few seconds.

## Importance of Mole

The concept of a mole has great importance in chemistry for many reasons. Some reasons are here:

·       With the use of moles, we can accurately calculate the ratio of various elements and compounds involved in chemical reactions.

·       The mole allows chemists to determine the ratio of different substances involved in chemical reactions. It is crucial for balancing equations and predicting reaction outcomes. By knowing the mole ratios, we can determine the amounts of substance required for a reaction and the amounts of the product that will be produced.

·       The mole is commonly used to express the concentration of a substance in a solution. This information is valuable in various fields such as medicine, environmental science, and industry.

·       By using the concept of moles, we can interchange the quantity of a substance’s mass with the number of moles. This information is crucial for making accurate measurements in chemical experiments.

## Solved Examples of calculating mole

Some solved examples of the mole are given below, which can help you understand it more easily.

Example 1.

Determine the number of moles in 10 grams of carbon.

Solution

Step 1. The mass of carbon is given. i.e.

Mass of carbon = 10 g

Step 2. Look at the periodic table.

Molar mass of carbon = 12.011 g/mol

Step 3. Write down the formula of the mole

Mole = Mass / Molar mass

Substitute these values in the formula of mole. i.e.

Mole of carbon = 10 / 12.011 = 0.832 mol

Approximately 0.832 moles are in 10 grams of Carbon.

Example 2.

Calculate the mass of 0.8 moles of Hydrogen gas.

Solution

Step 1.  Here,

A mole of Hydrogen gas (H2) = 0.8 mol

Step 2. Molar mass of H2 = (2 × 1.0078) g/mol = 2.0156 g/mol

Step 3. We have the following equation to find the mass of hydrogen gas.

Mass = Moles × Molecular weight

Put the above values in the formula of mass. i.e.

Mass = 0.8 × 2.0156 = 1.6124 grams

The mass of 0.8 moles of hydrogen gas is 1.6124 grams.