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