Question

Calculate mass of sodium which contains same number of atoms as are present in 20gram of calcium?

Answer 1

Mass of Ca = 20g

Moles of Ca = Given mass / Molar mass = 20/40 = 0.5 mol

1 mole of Ca = 6.02 x 10^23 atoms = 40g

0.5 mole of Ca = 0.5 x 6.02 x 10^23 = 3.01 x 10^23 atoms

Atoms of Na = 3.01 x 10^23

Moles of Na = Given atom / Atoms present in 1 mole = 3.01 x 10^23 / 6.02 x 10^23 = 0.5 mol

1 mole of Na = 6.02 x 10^23 atoms = 23g

Mass of Na = Moles x Molar mass = 0.5 x 23 = 11.5g