# introduction to Mole: Definition, formula, and Calculations

A mole is a unit of measurement in an International system unit (SI) that represents a specific amount of substance. 6.02 × 1023 Particles make up one mole, simply just like twelve eggs make a dozen. The number 6.02 × 1023 is known as Avogadro’s number and is represented as NA. Avogadro’s number tells us how many particles there are in one mole of a substance.

The mole plays an important role in chemistry as it allows chemists to make accurate quantitative predictions about chemical reactions and accurately determine the amounts of reactants and products involved in a given reaction.

In this article, we will explore the meaning of the term “mole” in chemistry, its importance, and how it is calculated with solved.

## What is a mole in chemistry?

A mole is a unit of measurement that is used to express the amount of substance in a chemical reaction. The term “mole” is defined as the quantity or mass of a substance that contains 6.02 × 1023 particles (atoms, molecules, or formula units).

The quantitative definition of a mole is the atomic mass, molecular mass, or formula mass of a substance expressed in grams. “mol” is the abbreviation used to represent this unit of measurement.

## Formula to find the number of moles of a substance

We can determine the number of moles of a substance with the help of the following formula

Mole = Mass / Molecular weight

To calculate the mass of a substance rearrange the above formula

Mass = Mole × Molecular weight

To calculate the molecular weight,

Molecular weight = Mass / Mole

• Mass: In chemistry, mass refers to the amount of matter in a substance and it measures in grams.
• Molecular weight: Molecular weight refers to the average mass of the molecule and is expressed in grams per mole.

A mole calculator is an online resource that can be used to find the unknown term (mole, mass, or molecular weight) with steps.

## Importance of mole

Here are some points that highlight the importance of mole in chemistry:

• It allows chemists to easily compare and calculate the amount of different substances involved in chemical reactions.
• It provides a way to convert between the mass of a substance and the number of its constituent particles (atoms, molecules).
• The mole helps chemists to determine the empirical and molecular formulas of compounds, which are essential to understanding a substance’s chemical properties and behavior.
• The mole is used to express the concentration of the solution, which is important in many applications such as medicine, environmental science, and industry.

## How to determine the mole of a substance?

To determine the mole of a substance, you can follow these steps:

1. Determine the mass of a substance in grams. This could be given in the problem or obtained by measuring the mass on a balance.
2. Find the molecular weight of the substance. This is the mass of one mole of a substance and is expressed in grams per mole (g / mol). The molar mass can be found on a periodic table.
3. Divide the mass of the substance (g) by the molecular weight (g/mol). This will give you the number of moles of the substance.

## Solved examples of mole

Here are some solved examples of the mole to understand it better.

### Example 1.

How many moles are in 15 grams of Hydrogen gas (H2)?

Solution

Step 1. Here, the mass of hydrogen is given.

Mass of Hydrogen= 15 g

Step 2. Observe the periodic table.

The molecular weight of hydrogen gas (H2) = 2 × 1.008 = 2.016 g/mol

(As 1.008 g/mol for each hydrogen atom)

Step 3. As we know that

Mole = Mass / Molecular weight

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

Mole = 15 / 2.016 = 7.44mol

Hence, approximately 7.44 moles are in 15 grams of hydrogen gas.

### Example 2.

Find the mass of 0.5 moles of carbon.

Solution

Step 1.  The mole of carbon is given.

Mole of carbon = 0.5 mol

Step 2. Molar weight of carbon C = 12.011 g/mol

Step 3. As we know that

Mass = Mole × Molecular weight

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

Mass = 0.5 × 12.011 = 6.005 grams

Therefore, the mass of 0.5 moles of carbon 6.005 is grams.

## Conclusion

In this article, we have discussed mole with its application in detail. We discussed the formula to find the number of moles in a substance, the mass of a substance, and molecular weight. We explained the importance of mole in chemistry. After this, we learn how to calculate the mole of a substance. At last, we solved some examples for you to understand it better. After reading this article, you will calculate the number of moles easily.

## FAQs

### What is the mole in chemistry?

In chemistry, a mole is a unit of measurement used to express the amount of a substance containing a large number of particles such as atoms, molecules, or ions.

### Why do we need to calculate mole?

The mole allows chemists to accurately measure the reactant needed to produce a specific product in a chemical reaction. By knowing the mole ratio between the reactant and products, chemists can predict the amount of product that will be formed.

### Are molecular weight and molar mass the same?

Molecular weight and molar mass are not exactly the same, but they are closely related terms. Molecular weight refers to the average mass of the molecule. On other hand, the molar mass is the mass of one mole of a substance.