How Can You Calculate the Mass of a Known Number of Atoms of an Element?

By Staff WriterLast Updated August 04, 2015

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To calculate the mass of a specific number of atoms of an element, divide the number of atoms by 6.02 x 10²³ and then multiply by the molar mass of the element. The process for calculating mass from the number of atoms is the same for all elements.

Step 1: Calculate the number of moles from the number of atoms.

Divide the number of atoms by 6.02 x 10

²³

, the number of atoms in one mole of the element — also known as Avogadro’s number.

Step 2: Determine the molar mass of the element.

The molar mass of an element is the mass in g of one mole of the element. Determine the molar mass by placing the units g/mol after the atomic weight of the element. (Atomic weight can be obtained from the periodic chart.)

Step 3: Multiply the number of moles of the element by the molar mass.