Propane (C3H8) Burns in the presence of oxygen to produce carbon dioxide and water. what mass of propane will combust using 8.35 moles of oxygen?

Question

C3H8 + 5O2 --> 3CO2 + 4 H2O

Answer 1

C₃H₈ + 5O₂ --> 3CO₂ + 4 H₂O

note that it takes FIVE moles of O₂ for every 1 mole of C₃H₈.

We know we are using 8.35 moles of O₂, so how many moles of C₃H₈ are needed?

8.35 mols O₂ x 1 mol C₃H₈ / 5 mols O₂ = 1.67 moles C3H8 needed

Now convert 1.67 moles C₃H₈ to grams using 44.1 g / mol as the molar mass

1.67 mols x 44.1 g / mol = 73.6 g C₃H₈