Question

Question 2. Calculate the mass percent of different elements present in sodium sulphate (Na2 SO4).​

Answer 1

Answer:

Molar mass of Na

2

SO

4

= 23×2+32+4×16=142

Na=

142

23×2

×100=32.4%

S=

142

32

×100=22.5%

O=

142

64

×100=45%

Answer 2

Answer

Molecular mass of sodium sulphate (Na 2SO4 ) is 142 g mole.

The elements present in sodium sulphate are sodium, sulphur, and oxygen.

Mass of sodium : 23×2=46g

Mass of sulphur : 32×1=32g

Mass of oxygen : 16×4=64g

Mass percentage of sodium = 32/142×100 = 32. 38 % ≈ 32.4 %

Mass percentage of oxygen = 64/142 ×100 = 45.05 %

Mass percentage of sulphur = (100 - 32.4 - 45.05) % = 22.55 %