- Start by writing the balanced combustion reaction of propane.
- From the mass of propane, we can use the balanced equation to get the moles of O
_{2 }by stoichiometry - Moles of O
_{2 }will be plugged into an ideal gas equation to find V of O_{2} - V of air will be calculated from V of O
_{2}using the information where 21% of air is made up of O_{2}

Propane, C_{3}H_{8}, is a hydrocarbon that is commonly used as a fuel.

Calculate the volume of air at 25°C and 1.00 atmosphere that is needed to completely combust 25.0 grams of propane. Assume that air is 21.0 percent O_{2} by volume. (Hint: we will see how to do this calculation in a later chapter on gases—for now use the information that 1.00 L of air at 25°C and 1.00 atm contains 0.275 g of O_{2} per liter.)