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

  1. Class 9
  2. Chapter 3 Class 9 - Atoms And Molecules (Term 2)

About the Author

CA Maninder Singh's photo - Founder at Teachoo
CA Maninder Singh
CA Maninder Singh is a Chartered Accountant for the past 11 years and a teacher from the past 11 years. He teaches Science, Accounts and English at Teachoo