Question

Calculate the percentage by weight of S if 160 grams of organic compound produce 466 grams of BaSO₄.

• A. 20%
• B. 25%
• C. 30%
• D. 35%

Hint:

When calculating percentage by weight, first find the mass of the element involved using stoichiometry and then divide by the total mass of the compound.

Answer 1

The Correct Option is B

The chemical reaction for the formation of BaSO₄ is: \[ \text{Organic compound} + BaCl_2 \rightarrow BaSO_4 + \text{Other products}. \] The molar mass of BaSO₄ is \( 137 + 32 + 4 \times 16 = 233 \) g/mol. From the given data, 160 grams of organic compound produces 466 grams of BaSO₄. Using stoichiometry, we can calculate the percentage by weight of sulfur (S) in the compound: \[ \text{Percentage of S} = \frac{\text{mass of S}}{\text{mass of organic compound}} \times 100 = \frac{466}{160} \times \frac{32}{233} \times 100 = 25\%. \] Thus, the correct answer is option (2) 25%.