Question

What is the mass of-
(a) 1 mole of nitrogen atoms?
(b) 4 moles of aluminium atoms (Atomic mass of aluminium = 27)?
(c) 10 moles of sodium sulphite (${\text{N}}{{\text{a}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{3}}}$)?

Answer 1

Hint: To solve this problem, you need to know about the mole concept as well. If you know the number of atoms in one mole, then you can solve this problem.

Complete step by step answer:
We know that one mole of atoms contains Avogadro number of particles. If you know the mass of one mole of an atom that is gram atomic mass (GAM), you can solve this problem easily. Let us look the problems one by one:

(a) We know that the atomic mass of nitrogen is 14.
${\text{Mass of nitrogen atom = Number of moles }} \times {\text{ Atomic mass}}$
So, mass of nitrogen = 1 × 14 = 14 g
Mass of one mole of nitrogen atoms is 14 g.

(b) We know that atomic mass of Aluminium = 27
Mass of aluminium atoms = number of moles × atomic mass
So, mass of 4 moles of aluminium = 4 × 27 = 108 g
Mass of four moles of aluminium is 108 g.

(c) We need to find the mass of one mole of sodium sulphite:
That is, $\left( {2 \times 23} \right) + 32 + \left( {3 \times 16} \right) = 126$
So, mass of 10 moles of sodium sulphite = 10 ×126 = 1260 g
Mass of ten moles of sodium sulphite is 1260 g.

Note: You must know that one mole contains Avogadro's number of particles. That is $6.022 \times {10^{23}}$ particles. We know that is a huge number which is only used in the case of atoms. So, one mole of nitrogen atoms means $6.022 \times {10^{23}}$ nitrogen atoms.