Question

The number of atoms present in 16 grams of helium is:

Answer 1

As we know,

4 grams of helium contain $6.022\times {10}^{23}$ atoms
1 grams of helium contain $\frac{6.022\times {10}^{23}}{4}$ atoms

Therefore
16 grams of helium contain $16\times \frac{6.022\times {10}^{23}}{4}$
$=24.088\times {10}^{23}$atoms of helium