Question

Calculate the mass of sulphur in 50g of sodium thiosulphate [Na=23,O=16,S=32]

Answer 1

MASS OF SULPHUR IN SODIUM THIOSULPHATE

$\\ \\ \sf Sodium \: thiosulphate \\ \quad \quad \sf \qquad Na_{2}S_{2}O_{3}$

Given, Mass:

• Na = 23
• O = 16
• S = 32

Molar mass of Sodium thiosulphate:

⇒ 23×2 + 32×2 + 16×3

⇒ 46 + 64 + 48

⇒ 158 g

Mass given of Sodium thiosulphate: 50 g

∴ No. of moles = Given mass / molar mass

⇒ no. of moles = 50/158

⇒ no. of moles = 0.31 mol

Concentration of Sulphur in 1 mol sodium thiosulphate = 64 g

So, In 0.31 mol:

⇒ 64 × 0.31

⇒ 19.84 g

Answer 2

Answer:

20.25g

Explanation:

Mass of Na2S2O3 = 23 + 2×32 + 3×16

= 158g

mass of sulphur = 32g

mass of S in Na2S2O3 = 32/158

=20.25g