A sample of a compound containing hydrogen, carbon, and sulfur is reacted with oxygen. The carbon content in the carbon dioxide obtained is 41.34% and the hydrogen content in the water obtained is 3.47%. Determine the empirical formula of the compound.

Question

A sample of a compound containing hydrogen, carbon, and sulfur is reacted with oxygen. The carbon content in the carbon dioxide obtained is 41.34% and the hydrogen content in the water obtained is 3.47%. Determine the empirical formula of the compound.​

Quizplus · Accepted Answer

Assume we have 100g of the compound. Then, we have 41.34g of carbon and 3.47g of hydrogen. The remaining mass is sulfur. 
Let's calculate the number of moles of each element: 
- Carbon: 41.34g / 12.01 g/mol = 3.44 mol
- Hydrogen: 3.47g / 1.01 g/mol = 3.44 mol
- Sulfur: (100g - 41.34g - 3.47g) / 32.07 g/mol = 1.56 mol
Divide each value by the smallest number of moles (1.56 mol) to get the empirical formula:
- Carbon: 3.44 mol / 1.56 mol = 2.205 ≈ 2
- Hydrogen: 3.44 mol / 1.56 mol = 2.205 ≈ 2
- Sulfur: 1.56 mol / 1.56 mol = 1
The empirical formula is therefore CS2H2S. The only choice that matches this formula is B.

A Sample of a Compound Containing Hydrogen, Carbon, and Sulfur