Question

An unknown organic compound (0.315 g) containing only C, H, and O produces 0.771 of CO₂ and 0.105 g of H₂O when it undergoes complete combustion. The approximate molar mass is 108 g/mol. Which of the following compounds could be the identification of the unknown?

1,2-Benzoquinone, C₆H₄O₂

Answer 1

To identify the unknown organic compound, we can use the masses of CO₂ and H₂O produced during its combustion to calculate the masses of carbon and hydrogen in the sample.

Step-by-step explanation:

Upon combustion, 1 mol of CO₂ is produced for each mole of carbon atoms in the original sample. Similarly, 1 mol of H₂O is produced for every 2 mol of hydrogen atoms present in the sample. The masses of carbon and hydrogen in the original sample can be calculated from these ratios, the masses of CO₂ and H₂O, and their molar masses. Because the units of molar mass are grams per mole, we must first convert the masses from milligrams to grams: