Question

An unknown compound contains only carbon, hydrogen, and oxygen (CxHyOz). Combustion of 5.50 g of this compound produced 8.07 g of carbon dioxide and 3.30 g of water.

a) C₃H₆O
b) C₄H₈O₂
c) C₂H₄O
d) C₅H₁₀O₂

Answer 1

The empirical formula of the unknown compound is C₃H₆O.

Step-by-step explanation:

The given amounts of carbon dioxide and water produced during the combustion of an unknown compound can be used to determine the empirical formula of the compound. To do this, calculate the moles of carbon dioxide and water produced. From the balanced equation for combustion, we know that 1 mole of carbon dioxide is produced for every mole of carbon in the compound, and 1 mole of water is produced for every 2 moles of hydrogen in the compound.

1. Calculate the moles of carbon dioxide produced: 8.07 g CO₂ × (1 mol CO₂ / 44.01 g CO₂) = 0.183 mol CO₂
2. Calculate the moles of water produced: 3.30 g H₂O × (1 mol H₂O / 18.02 g H₂O) = 0.183 mol H₂O
3. Since the ratio of carbon dioxide to water is 1:1 in the combustion reaction, the moles of carbon and hydrogen in the compound must be equal. Therefore, the empirical formula of the unknown compound is C₃H₆O.