# If the atomic weight of an element is x, what is the mass in grams of 3.17 * 1020 atoms of the element?

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gsenviro | Certified Educator

Given the atomic weight of a substance, we can calculate the mass of a given number of atoms by converting them to moles. We know that one mole of a substance contains an Avogadro's number of atoms or 6.023 x 10^23 atoms.

that is, 6.023 x 10^23 atoms constitute one mole of a substance. Here we have 3.17 x 10^20 atoms.

Number of moles of the element = `(3.17 xx 10^20)/ (6.023 xx 10^23) = 5.26 xx 10^(-4)`

The atomic weight of the element = x gm/mole

Thus the mass of the given number of atoms can be calculated by multiplying the number of moles by atomic weight as:

Mass of atoms = **5.26 x 10^-4 x** gm.

Thus, we can use the mole concept to determine the mass of a given number of atoms of an element with a known atomic weight.

Hope this helps.