Question

What is the mass of 5 moles of sodium carbonate (Na2CO3) ?

(Atomic masses : Na = 23 u ; C = 12 u ; O = 16 u)

Answer 1

Number of moles of sodium carbonate = 5 moles
Molar mass of sodium carbonate = (2 × 23) + (1 × 12) + (3 × 16) = 106g

We know that 1 mole of sodium carbonate weighs 106g.

Mass of 5 moles of sodium carbonate = 5 × 106 = 530g

Hence, 5 moles of sodium carbonate weigh 530 grams.