The complete combustion of propane (C3H8) in the presence of oxygen yields CO2 and H2O: C3H8 (g) + 5O2 (g) 3CO2 (g) + 4H2O (g) a. Calcluate the volume of carbon dioixde (at s. T. P.) that would be produced by the combustion of 27.5 g of C3H8 burns in the presence of 45.0 L of O2.

26.9 L is the volume of CO₂, we obtained

Explanation:

The reaction is: C₃H₈ (g) + 5O₂ (g) → 3CO₂ (g) + 4H₂O (g)

Let's determine the reactants moles:

27.5 g. 1mol / 44 g = 0.625 moles

We need density of O₂ to determine mass and then, the moles.

O₂ density = O₂ mass / O₂ volume

O₂ density. O₂ volume = O₂ mass

1.429 g/L. 45L = O₂ mass → 64.3 g

Moles of O₂ → 64.3 g. 1mol/32g = 2.009 moles

Let's find out the limiting reactant:

1 mol of propane needs 5 moles of oxygen to react

Then, 0.625 moles will react with (0.625. 5) / 1 = 3.125 moles of O₂

Oxygen is the limiting reactant, we need 3.125 moles but we only have 2.009 moles

Ratio is 5:3. 5 moles of O₂ produce 3 moles of CO₂

Therefore, 2.009 moles of O₂ must produce (2.009.3) / 5 = 1.21 moles of CO₂. Let's find out the volume, by Ideal Gases Law (STP are 1 atm and 273K, the standard conditions)

1 atm. V = 1.21 moles. 0.082. 273K

V = (1.21 moles. 0.082. 273K) / 1atm = 26.9 L