Answer to Question #147480 in Chemistry for Kristia Anne Panares

Question

What mass of Na2S2O3 is needed to react with 0.12 g of Cl2?

Answer 1

Solution:

The balanced chemical equation:

Na₂S₂O₃(aq) + 4Cl₂(g) + 5H₂O(aq) --> 2NaHSO₄(aq) + 8HCl(aq)

According to the equation: n(Na₂S₂O₃) = n(Cl₂)/4

Moles of Cl₂ = n(Cl₂) = Mass of Cl₂ / Molar mass of Cl₂

The molar mass of Cl₂ is 70.9 g mol^-1.

n(Cl₂) = 0.12 g / 70.9 g mol^-1 = 0.00169 mol = 0.0017 mol

n(Na₂S₂O₃) = n(Cl₂)/4

n(Na₂S₂O₃) = 0.0017 mol / 4 = 0.000425 mol

Moles of Na₂S₂O₃ = n(Na₂S₂O₃) = Mass of Na₂S₂O₃ / Molar mass of Na₂S₂O₃

The molar mass of Na₂S₂O₃ is 158.11 g mol^-1.

Hence,

Mass of Na₂S₂O₃ = n(Na₂S₂O₃) × M(Na₂S₂O₃)

Mass of Na₂S₂O₃ = 0.000425 mol × 158.11 g mol^-1 = 0.067 g

Mass of Na₂S₂O₃ is 0.067 grams.

Answer: 0.067 g of Na₂S₂O₃ is needed to react with 0.12 g of Cl₂.