Which of the following best describes the concept of molar mass?

Molar mass is defined as the mass of one mole of a substance, whether it be an element or a compound, expressed in grams. This is calculated by summing the atomic masses of all the atoms in a molecule based on the periodic table, which is typically presented in grams per mole (g/mol). For instance, the molar mass of water (H₂O) can be calculated by taking the atomic mass of hydrogen (approximately 1 g/mol) and oxygen (approximately 16 g/mol), leading to a total molar mass of about 18 g/mol.

This definition is essential in stoichiometry, where understanding the relationship between the mass of substances and their amounts in moles is crucial for performing calculations in chemical reactions. Knowing the molar mass allows chemists to convert grams of a substance into moles, facilitating the use of the ideal gas law, reaction yields, and other quantitative analyses in chemistry.

The other choices do not accurately represent the concept of molar mass: while one describes atomic mass, another refers to the calculation of moles from a given mass, and the last considers properties of gases rather than mass relationships directly linked to moles.