need chemistry help

Question

If 2.21 moles of propane (C3H8) react with excess oxygen in a complete combustion reaction, how many moles of water are produced?

Answer 1

Write the correctly balanced equation:

C₃H₈ + 5O2 ==> 3CO₂ + 4H₂O ... balanced equation for combustion of propane

This tells us that for every mole of C3H8, you get 4 moles H2O

2.21 moles C3H8 x 4 moles H2O / mole C3H8 = 8.84 moles H2O