Difference Between Molar Mass and Molecular Mass

Difference Between Molar Mass and Molecular Mass: Chemistry is a branch of science, that has a primary focus on measuring the mass of any substance. In this vast field of Chemistry, various terms are used regularly. Two such terms that are frequently used are Molar Mass and Molecular Mass. At this point, these two terms sound familiar to each but don’t get confused as they do possess a lot of differences that we are going to discuss in the later part of this article. The main difference between molecular mass and molar mass is that molar mass is the weight of a mole of atoms or molecules, while molecular mass is the total weight of all the atoms in a molecule.

In this article, you will learn about what is molar mass, what is molecular mass, the difference between molar mass and molecular mass, and the similarities between molar mass and molecular mass.

What is Molar Mass?

Molar mass is also known as relative molar mass. In simple words, the molar mass is the mass of any substance. It is represented by g/mol which specifies the number of molecules, atoms, or compounds that are stored by one mole of a substance. It denotes the mass of one mole of a substance.

How Molar Mass is Measured?

Molar Mass is represented by g/mol which specifies the number of molecules, atoms, or compounds that are stored by one mole of a substance. To proceed further, one needs to refer to the periodic table that displays the molar mass of every element. The sum of the atomic masses of the constituent atoms is calculated to measure the molar mass of compounds

What is Molecular Mass?

Molecular Mass is the mass of the molecules. The amu is the unit for measuring the Molecular Mass. The variation of molecular mass is because of the isotopes. Its main role is to determine the mass of the molecules. It has the potential to provide insights about the molecule such as its composition and structure.

How Molecular Mass is Measured?

To measure the molecular mass, we calculate the sum of the atomic masses of all the atoms in a molecule. The amu is the unit for measuring the Molecular Mass. Mass spectrometry is one common technique that can be used to measure the molecular mass. It can successfully determine the mass-to-charge ratio of ions. X-ray crystallography and nuclear magnetic resonance (NMR) spectroscopy are a couple of more techniques that can be used to measure molecular mass.

Read More: How to Calculate Molecular Formula of Compounds?

What is the difference between Molar Mass and Molecular Mass?

The most prominent difference between Molecular Mass & Molar Mass is that molecular mass is mainly focused on the mass of a single molecule, whereas on the other hand molar mass deals with the mass of one mole of that substance. Another main difference is that the molecular mass describes the weight of a single entity, whereas molar mass is generally used in measuring the weight of a specific number of entities (Avogadro’s number) of that substance.

Tabular Difference Between Molar Mass and Molecular Mass

Here are the points of difference between Molar Mass and Molecular Mass :

SR No.	Molar Mass	Molecular Mass
1)	It is the mass of one mole of a substance.	It is the mass of molecules.
2)	Denoted by g/mol.	Denoted by Amu.
3)	It is used in complex calculations	It is used to compare the masses of different molecules.
4)	Less accurate.	Highly accurate.
5)	Contains dimensions of grams per mole	Dimensionless.
6)	Remains constant.	Varies based on the isotopes.
7)	Property of a substance	Property of a molecule within a substance
8)	Directly related to molar volume.	No relationship with molar volume.

Summary – Molar Mass vs Molecular Mass

In conclusion, one thing that we have acquainted with the is that in the vast realm of Chemistry, the terms Molar Mass and Molecular Mass stand tall as the most frequently used terms. Despite the molar mass and molecular mass sounding similar, they do have a handful of differences between them. If anyone wished to delve deep down into the composition and structure of any substance, then the focus is on Molar Mass. When it comes to measuring the mass of a molecule, the concept of Molecular Mass comes into play. It possesses the properties of being highly accurate and dimensionless. In the symphony of Chemisty, both Molar Mass and Molecular Mass play a crucial role and have the utmost importance.

FAQs on Difference Between Molar Mass and Molecular Mass

1. Can molar mass and molecular mass be equal for a substance?

No, molar mass and molecular mass cannot be equal. The simple reason for the above is that Molar mass is the mass of one mole of a substance, and molecular mass is the sum of the atomic masses within a molecule.

2. Are molar mass and molecular mass affected by temperature and pressure?

No, molar mass and molecular mass are not directly affected by temperature and pressure. Although one thing that must be noted is that the changes in temperature and pressure can affect physical properties such as volume, density, etc. Due to this, there can be a certain change in the calculation that involves molar mass or molecular mass.

3. Are molar mass and molecular mass the same for isotopes of an element?

No, molar mass and molecular mass are different for isotopes of an element. Isotopes can be considered as the variant of an element that contains the same number of protons but different neutrons. As we know, the number of neutrons plays a part in a mass of an atom, isotopes of an element have different molar masses. On the other hand, if a molecule possesses atoms of varied isotopes, the molecular mass will be affected.

4. Why is molar mass important in chemical reactions?

Molar mass is mainly needed for stoichiometry, which is mainly used in order to relate the amounts of reactants and products in a chemical reaction.

5. What units are used to express molecular mass?

Molecular mass is usually expressed in atomic mass units (amu) or unified atomic mass units (u).