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
