Question

Calculate the mass percent of different elements in sodium sulphate $N{a}_{2}S{O}_4$?

• A. Mass% of Na is 32.5%, Mass% of S is 22.5%, Mass% of O is 45%
• B. Mass% of Na is 32.5%, Mass% of S is 45%, Mass% of O is 22.5%
• C. Mass% of Na is 45%, Mass% of S is 22.5%, Mass% of O is 32.5%
• D. Mass% of Na is 22.5%, Mass% of S is 32.5%, Mass% of O is 45%

Answer 1

The correct option is A

Mass% of Na is 32.5%, Mass% of S is 22.5%, Mass% of O is 45%

Molecular weight of $N{a}_{2}S{O}_4$ = $23\times 2+32+16\times 4$

=46+32+64 = 142 g

Mass% = $\frac{Massofelementpresentinthecompound\times 100}{Totalmassofthecompound}$

Mass of Sodium in this compound = 46 g

Mass% of Sodium in this compound = $\frac{46\times 100}{142}$ = 32.5%

Mass of Sulphur in this compound = 32 g

Mass% of Sulphur in this compound = $\frac{32\times 100}{142}$ = 22.5%

Mass of Oxygen in this compound = 64 g

Mass % of Oxygen in this compound = $\frac{64\times 100}{142}$ = 45%