Question

Knowing the molar mass and Avogadro's number, we can calculate the mass of a single atom in grams. For example, we know the molar mass of carbon-12 is 12 g and there are 6.022 × 1023 carbon-12 atoms in 1 mole of the substance; therefore, the mass of one carbon-12 atom is given by

Answer 1

The molar mass is the mass of 1 mole of a substance, which is equal to the mass in grams of 6.022 × 10²³ particles of that substance. For carbon-12, the molar mass is precisely 12 g/mol, allowing calculation of the mass of a single carbon atom using Avogadro's number.

Step-by-step explanation:

The concept of molar mass is a fundamental aspect of chemistry that allows us to relate the mass of a substance to the number of particles it contains. By definition, the molar mass of a substance is the mass in grams of 1 mole of that substance. An isotopically pure mole of carbon-12, which serves as the standard for the atomic mass unit, has a molar mass of 12 g.

Using Avogadro's number, which is approximately 6.022 × 10²³, we can determine the mass of a single atom in grams. For carbon-12, since its molar mass is exactly 12 g/mol, the mass of a single carbon-12 atom is calculated by dividing the molar mass by Avogadro's number.

To generalize, if an element has an atomic mass of X amu, then the molar mass of that element is X g/mol. In practical terms, to convert the number of moles of a substance to its mass, you multiply by the molar mass, and to find the number of moles from a given mass, you divide the mass by the molar mass.