Balance Chemical Equation for combustion of Propane is as follow,
C₃H₈ + 5 O₂ → 3 CO₂ + 4 H₂O
According to equation,
1 mole of C₃H₈ on combustion gives = 4 moles of H₂O
So,
5 moles of C₃H₈ on combustion will give = X moles of H₂O
Solving for X,
X = (5 mol × 4 mol) ÷ 1 mole
X = 20 moles of H₂O
Calculating number of molecules for 20 moles of H₂O,
As,
1 mole of H₂O contains = 6.022 × 10²³ molecules
So,
20 moles of H₂O will contain = X molecules
Solving for X,
X = (20 mole × 6.022 × 10²³ molecules) ÷ 1 mol
X = 1.20 ×10²⁵ Molecules of H₂O