Difference Between Molar Mass and Molecular Mass

Thekey differencebetween molar mass and molecular mass is that themolar mass gives the average mass of the molecule whereas the molecular mass gives the mass of a singlemolecule。

Atoms can join together in various combinations to form molecules and other compounds. Molecular structures give the exact ratios of atoms; thus, we can write molecular formulas for compounds. These are important in determining the molecular masses or molar masses. We can characterize molecules with their masses. Knowing this is really useful in laboratory work when measuring the compounds for reactions.

内容

1.Overview and Key Difference
2.What is Molar Mass
3.What is Molecular Mass
4.Side by Side Comparison – Molar Mass vs Molecular Mass in Tabular Form
5.概括

什么是摩尔质量？

We can call molar mass as molecular weight as well. Thus, it is the mass of a substance for a given amount. The SI unit for the molar mass is g mol^-1。这给出了一种物质中存在的原子/分子/化合物的量。换句话说，它是Avogadro数量原子/分子或化合物的质量。

It is important to measure the weight of atoms and molecules in the practical scenario. But it is difficult to weigh them as individual particles, since their masses are really small according to the normal weighing parameters (such as grams or kilograms). Therefore, to fulfill this gap and to measure the particles in a macroscopic level molar mass concept is useful.

Difference Between Molar Mass and Molecular Mass

Figure 01: A Triatomic Molecule

The definition of molar mass is directly related to thecarbon-12 isotope。The mass of onemoleof carbon-12 atoms is exactly 12 grams, which is its molar mass, it is exactly 12 grams per mole. We can calculate the molar mass of molecules containing the same atom like O₂or N₂通过将原子数量乘以原子的摩尔质量。此外，我们可以计算NaCl或CUSO等化合物的摩尔质量₄通过添加每个原子的原子质量。

What is Molecular Mass?

化合物的分子质量是一个帽的质量lecule. We can measure this usingatomic mass units (amu)。1 atomic mass unit is the one-twelfth of the mass of a C-12 isotope. When we divide the mass of a molecule by the mass of one-twelfth of the mass of a C-12 isotope, we get the relative mass. Furthermore, molecular mass differs according to the isotopes that the molecule contains. When calculating the molecular mass, we should consider the relevant isotopic mass.

What is the Difference Between Molar Mass and Molecular Mass?

Molecular mass gives the mass of a single molecule (sum of the atomic masses in the molecule), whereas molar mass gives the average mass of the molecule (mass of Avogadro number of molecules). Hence, this is the key difference between molar mass and molecular mass. Therefore, the molecular mass of a molecule containing heavier isotopes can be few units higher than the molar mass. Otherwise, the value of the molar mass and molecular mass is quite the same for a similar molecule; only the units are different. One significant difference between molar mass and molecular mass is that the unit of the molecular mass is amu, and the unit of the molar mass is gmol^-1。

Furthermore, it is accurate to use the molecular mass in calculations of higher amounts of molecules than using the molar mass. Moreover, in measurement, one difference between molar mass and molecular mass is that the molar mass is a measurement, which we can give for an atom, molecule or compound. But we can determine the molecular mass only in the molecules. If it is the mass of an atom, we use different terminology; atomic mass.

The below infographic presents the difference between molar mass and molecular mass in tabular form.