Question

A certain alcoholic beverage contains only ethanol (C2H6O) and water. When a sample of this beverage undergoes combustion, the ethanol burns but the water simply evaporates and is collected along with the water produced by combustion. The combustion reaction is: C2H6O(l) + 3O2(g) → 2CO2(g) + 3H2O(g) when a 10.00 g sample of this beverage is burned, 11.27 g of water is collected. a) What is the mass of ethanol in the original sample? Enter a numerical answer in grams.

Answer 1

Answer:

9.606 g

Explanation:

Step 1: Write the balanced combustion reaction

C₂H₆O(l) + 3 O₂(g) → 2 CO₂(g) + 3 H₂O(g)

Step 2: Calculate the moles corresponding to 11.27 g of H₂O

The molar mass of H₂O is 18.02 /mol.

11.27 g × (1 mol/18.02 g) = 0.6254 mol

Step 3: Calculate the moles of C₂H₆O that formed 0.6254 moles of H₂O

The molar ratio of C₂H₆O to H₂O is 1:3. The moles of C₂H₆O are 1/3 × 0.6254 mol = 0.2085 mol

Step 4: Calculate the mass corresponding to 0.2085 moles of C₂H₆O

The molar mass of C₂H₆O is 46.07 g/mol.

0.2085 mol × 46.07 g/mol = 9.606 g