Given:
Mass of He (m) = 52g
Atomic mass of He = 4u
Molar mass of He (M) = 4g/mol
To calculate the number of moles, we will apply the formula given below:
Number of moles = \(\frac{Given\,mass\,(m)}{Molar\,mass\,(M)}\)
Number of moles = \(\frac{52g}{4g/mol}\)
Number of moles = 13
Thus, the number of moles in 52 g of He is 13.