Answer:
85.6 g
Explanation:
Step 1: Write the balanced combustion equation
C₃H₈ + 5 O₂ ⇒ 3 CO₂ + 4 H₂O
Step 2: Calculate the moles corresponding to 140 g of H₂O
The molar mass of H₂O is 18.02 g/mol.
140 g × 1 mol/18.02 g = 7.77 mol
Step 3: Calculate the moles of C₃H₈ needed to produce 7.77 moles of H₂O
The molar ratio of C₃H₈ to H₂O is 1:4. The moles of C₃H₈ needed are 1/4 × 7.77 mol = 1.94 mol.
Step 4: Calculate the mass corresponding to 1.94 moles of C₃H₈
The molar mass of C₃H₈ is 44.10 g/mol.
1.94 mol × 44.10 g/mol = 85.6 g
