Question

Combustion analysis of a 13.42 g sample of estriol (which contains only carbon, hydrogen, and oxygen) produced 36.86 g of CO₂ and 10.06 g of H₂O. The molar mass of estriol is 288.38 g/mol. Find the molecular formula for estriol.

Answer 1

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.

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: