Question

Calculate the no of atoms in each of the following

(a) 52 moles of Ar

(b) 52 g of He​

Answer 1

Answer:

(i) 52 moles of Ar

we know,

1 mole of Ar = 6.022 × 10²³ atoms

52 mole of Ar = 52 × 6.022 × 10²³ atoms

= 313.144 × 10²³ atoms

= 3.13144 × 10²⁵ atoms

________________________________

(ii) 52u of He

we know,

mass of 1 atom of He = 4u

e.g., 4u of He = 1 He atom

∴ 1u of He = 1/4 He atom

∴ 52u of He = 52/4 He atoms = 13 He atoms

Answer 2

Answer:

a) 3.132×10²⁵. b)7.83×10²⁴

Explanation:

Each mole of substance contain avogadro number(6.023×10²³) of atoms , here the number of mole of Ar and He present respectively are 52 and 13.