How many moles are in 1.78 x 1050 atoms of Mg?

0.296×10²⁷ moles of Mg atoms.

Explanation:

Given data:

Number of moles of Mg = ?

Number of atoms = 1.78 ×10⁵⁰ atom

Solution:

Avogadro number:

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.  The number 6.022 × 10²³ is called Avogadro number.

For example,

18 g of water = 1 mole = 6.022 × 10²³ molecules of water

1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen

Number of moles of Mg atoms:

1.78 ×10⁵⁰ atom × 1 mol  /6.022 × 10²³ atoms

0.296×10²⁷ moles of Mg atoms.