Calculate the Number of Atoms in Each of the Following (i) 52 Moles of Ar (ii) 52 u of He (iii) 52 g of He

Answer: The nature of helium is monoatomic. One mole of any substance mainly contains 6.022×10²³ atoms of Ar. So, the 52 moles of Ar generally have 52 x 6.022 x 1023 atoms.

The atomic mass of each He is 4.003, to be precise. That means the group of each atom is 4.003 amu. Then the 52 u of He has 52/4.003, which is 12.99 means 13. So, 52 u of He has 13 atoms.

The g atomic mass of each He is 4.003 g. So, 4.003 g of He has 6.022 × 10²³ atoms. Then that means 52 g of He has 13 moles (52/4). 

Thirteen moles of He contain 13 × 6.022 × 10²³ atoms, which is 78.29× 10²³. Then 52 g of He mainly contains 7.829 × 10²⁴ atoms.