Calculate the number of atoms in each of the following :
(i) 52 moles of He
(ii) 52 amu of He
(iii) 52 grams of He.

Explanation

a. `1` mol of `He=6.022xx10^(23)` atoms
`:. 52 mol` of `He=52xx6.022xx10^(23)` atoms
`=3.131xx10^(25)` atoms
b. `1` atom of `He=4 u` of `He`
`4 u` of `He=1` atom of He
`:. 52 u` of `He=1/4xx52` atoms`=13` atoms
c. `1` mole of `He=4 g=6.022xx10^(23)` atoms
`:. 52 g` of `He=(6.022xx10^(23))/4xx52` atoms
`=7.8286xx10^(24)` atoms