Which of the following pairs have the same number of atoms?

A - 16 g of O ₂ (g) and 4 g of H ₂ (g)

B - 16 g of O ₂ and 44 g of H ₂

C - 28 g of N ₂ and 32 g of O ₂

D - 12 g of C(s) and 23 g of Na(s)

Answer

C - 28 g of N ₂ and 32 g of O ₂

D - 12 g of C(s) and 23 g of Na(s)

Explanation:

One mole of any species (atoms,molecules, ions or particles) is that quantity in number having a mass equal to its atomic or molecular mass in grams.

1 mole of an item = 6.022 x 10 ²³ items

In 28 g of N ₂ and 32 g of O ₂

• 28 g of N ₂ = 1 mole of N ₂ = 2 x 6.022 x 10 ²³ atoms
• 32 g of O ₂ = 1 mole of O ₂ = 2 x 6.022 x 10 ²³ atoms

In 12 g of C(s) and 23 g of Na(s)

• 12 g of C(s) = 1 mole of C = 6.022 x 10 ²³ atoms

23 g of Na(s) = 1 mole of C = 6.022 x 10 ²³ atoms