if 24 grams of propane(CO2) are produced from the reaction below, and you are told there is excess oxygen (O2) present, how many grams of C3H8 did you start with?

Answer 1

Jerry question is worded wrong, I do not want to give the wrong answer, and I am changing the question like this.

24 g of Carbon dioxide is produced, not propane

24 g of CO₂ 1 mol CO₂ 1 mol C₃H₈ 44 g of C₃H₈ = 24 * 44 = 8 g of C3H8

44 g CO₂ 3 mol CO₂ 1 mol C₃H₈ 44 * 3

Please know that the molar mass is almost the same for both and they react in a 1: 3-mole ratio.

You can find the combustion of propane on the web which is 1:3 ratio