In the following reaction, how many liters of oxygen will react with 124.5 liters of propane (C3H8), at STP?

Question

C3H8 + 5O2 = 3CO2 + 4H2O

Answer 1

Since all are gases one may use a shortcut that tells us we can use liters directly as moles. All you need to do is to convert 124.5 L propane to oxygen using the coefficients in the balanced equation.
124.5L x (5 moles propane/1 mol oxygen) = ? L O2.

Answer 2

662.5 liters

Answer 3

622.5 not 662.5

Answer 4

662.5