Grams of a substance divided by moles of the substance equals which quantity?

• A. molar mass in g/mol
• B. density in g/mL
• C. volume in liters
• D. mass in grams

Answer: (A)

Grams divided by moles gives the molar mass. This quantity, measured in grams per mole (g/mol), tells you how much mass one mole of a substance has and serves as the conversion factor between mass and amount. For example, if you have 12.0 g of carbon-12 and that amount corresponds to 1.00 mole, the molar mass is 12.0 g/mol. The other options describe different properties: density is mass per volume, volume is a measure of space, and mass is simply grams. So the quotient of grams divided by moles is the molar mass.