Question

calculate the number of atoms in 52 moles of helium

Answer 1

We know that for any element (and indeed any substance):

1 mole of that element = 6.022 x 10^23 atoms of that element - Avogadro's Number (approximately)

So, if we had 52 moles of Helium:

1 mole = 6.022 x 10^23 atoms of He
52 moles = (52)(6.022 x 10^23) atoms of He which, if you work out, should give you you're answer!