3.311x divided by 10^25 particles=? moles

5.5 moles of given substance.

Explanation:

The given problem can be solved by using the 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

Solution:

3.311 * 10²⁵ / 6.022 * 10²³ = moles

5.5 moles of given substance.