Question

Calculate the number of particles in
A) 0.1 mole of carbon atom
B) 8 grams of oxygen molecules
C) 46 grams of sodium atoms

Answer 1

1-) 1 Mole of C = 12 grams = 6.023 X 10 23atoms
0.1 Moles of C = 0.1 X 6.023 X 10 23atoms
= 6.023 X 10 22atoms

Therefore 0.1 moles of Carbon contain 6.023 X 10 22atoms
2-)Molecular Mass of O2 = 16 + 16 = 32 U (O + O)
Therefore
1 Mole of O2 = 32 grams
8 grams = 8/32 Moles
= 0.25 moles
= 0.25 X 6.023 X 10 23atoms
= 1.50 X 10 23atoms (Approximate)

Therefore 8 grams of O2 contain 1.50 X 10 23atoms
3-)Atomic Mass of Na = 23 U
Therefore 1 Mole of Na = 23 grams = 6.023 X 10 23atoms
46 grams of Na = 46/23 Moles
= 2 Moles

1 Mole = 6.023 X 10 23atoms
2 Moles = 6.023 X 10 23 X 2

= 12.046 X 10 23atoms