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Avogadro's Number Example Chemistry Problem

Finding Mass of a Single Atom

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You can apply Avogadro's number to determine the mass of one atom.

You can apply Avogadro's number to determine the mass of one atom.

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Avogadro's Number Example Problem - Mass of a single atom

Question: Calculate the mass in grams of a single carbon (C) atom.

Solution

To calculate the mass of a single atom, first look up the atomic mass for carbon from the Periodic Table.
This number, 12.01, is the mass in grams of one mole of carbon. One mole of carbon is 6.022 x 1023 atoms of carbon (Avogadro's number). This relation is then used to 'convert' a carbon atom to grams by the ratio:

mass of 1 atom / 1 atom = mass of a mole of atoms / 6.022 x 1023 atoms

Solve for mass of 1 atom

mass of 1 atom = mass of a mole of atoms / 6.022 x 1023

mass of 1 C atom = 12.01 g / 6.022 x 1023 C atoms
mass of 1 C atom = 1.994 x 10-23 g

Answer

The mass of a single carbon atom is 1.994 x 10-23 g .

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