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# 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 (Na$$_2$$SO$$_3$$)?

(a) Atomic mass of nitrogen atoms = 14u

Mass of 1 mole of nitrogen atoms= Atomic mass of nitrogen atoms

Therefore, mass of 1 mole of nitrogen atom is 14g

(b) Atomic mass of aluminium =27u

Mass of 1 mole of aluminium atoms = 27g

1 mole of aluminium atoms = 27g $$\Rightarrow$$ 4 moles of aluminium atoms = 4 × 27 = 108g

(c) Mass of 1 mole of sodium sulphite Na$$_2$$SO$$_3$$
= Molecular mass of sodium sulphite
= 2 × Mass of Na + Mass of S + 3 × Mass of O
= (2 × 23) + 32 +(3 × 16) = 46 + 32 + 48 = 126g

Therefore, mass of 10 moles of Na$$_2$$SO$$_3$$ = 10 × 126 = 1260g