Calculate the number of atoms in each of the following:

(i) 52 moles of He,

(ii) 52 u of He,

(iii) 52 g of He.

(i) 1 mole of Helium (He) contains

= 6.023 x ${{10}^{23}}$ atoms

52 moles of He contains = 6.023 x ${{10}^{23}}$ x 52 atoms.

= 3.13 x ${{10}^{-25}}$atoms

(ii) 4 u of Helium (He) = 1 atoms of He

52 u of He = 1/4x 52 = 13 atoms

(iii) 4 g of He contains = 6.023 x ${{10}^{-23}}$ atoms

52 g of He contains =6.023 x${{10}^{23}}$ x52/4= 7.8286 x ${{10}^{24}}$ atoms