Calculate the mass, in grams, of each sample. a. 1.1×10²³ gold atoms b. 2.82×10²² helium atoms

Key Concepts

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). For gold (Au), the molar mass is approximately 197 g/mol. This value is essential for converting between the number of atoms and the mass of the substance, as it allows us to relate the atomic scale to macroscopic quantities.

Avogadro's Number

Avogadro's number, approximately 6.022 x 10^23, is the number of atoms, ions, or molecules in one mole of a substance. This constant is crucial for converting between the number of individual particles and the amount of substance in moles, enabling calculations involving atomic quantities and their corresponding masses.

Mass Calculation

To calculate the mass of a sample based on the number of atoms, one must first convert the number of atoms to moles using Avogadro's number. Then, by multiplying the number of moles by the molar mass of the substance, the total mass in grams can be determined. This process is fundamental in stoichiometry and quantitative chemistry.