The combustion of propane (C3H8) in the presence of excess oxygen yields CO2 and H2O:

C3H8 (g) + 5O2 (g) → 3CO2 (g) + 4H2O (g)

When 2.5 mol of O2 are consumed in their reaction, mol of CO2 are produced.

1.5 moles

Explanation:

Given data:

Number of moles of O₂ consumed = 2.5 mol

Moles of CO₂ produced = ?

Solution:

Chemical equation:

C₃H₈ + 5O₂    →     3CO₂ + 4H₂O

Now we will compare the moles of oxygen with carbon dioxide from balance chemical equation:

                             O₂             :           CO₂

                               5             :            3

                              2.5           :         3/5×2.5 = 1.5

Thus from 2.5 moles of oxygen 1.5 moles of carbon dioxide are produced.