Question

Calculate the number of atoms in 52u of He

Answer 1

Dear Student

The atomic mass of He is 4 amu. So

4 amu of He = 1 atom of He

thus 1 amu of He = (1 / 4) atom of He

So 52 amu of He = (52 / 4) atom of He = 13 atoms of He

As the molar mass is the atomic mass of an element expressed in grams, therefore the number of moles in 52 g of He would be

= (mass / molar mass)

= 52 / 4 = 13

Now 1 mole of He atom = 6.023 X 10²³ atoms of He.

Therefore 13 moles of He atom = 13 X 6.023 X 10²³ atoms of He = 7.823 X 10²⁴ atoms of He