Question

1) 1C 3 H 8 + 5O 2 à 3CO 2 + 4H 2 O
a. How many moles of carbon dioxide gas is produced when 10.0 moles of propane, (C 3 H 8 ), is
burned in oxygen?
b. How many moles of oxygen gas are needed to produce 20 moles of water?

Answer 1

Use the balanced equation: C3H8 + 5 O2 → 3 CO2 + 4 H2O

a) 1 mol C3H8 → 3 mol CO2, so 10.0 mol C3H8 → 10.0 × 3 = 30.0 mol CO2.

b) 5 mol O2 → 4 mol H2O, so O2 needed = (5/4) × moles H2O = (5/4) × 20 = 25.0 mol O2.