Question

What is the number of sodium ions present in 0.2 moles of sodium oxide ?

Answer 1

1 mole of sodium oxide contains = 6.022$\times$10²³ molecules
0.2 mole = 0.2$\times$6.022$\times$10²³ = 1.2044$\times$10²³ molecules
1 molecule of Na₂O contains 2 ions of Na⁺
Therefore , 0.2 mole of sodium oxide contains = 2 $\times$1.2044$\times$10²³ ions = 2.4088$\times$10²³ ions