Gaseous ethane will react with gaseous oxygen to produce gaseous carbon dioxide and gaseous water . Suppose 17. g of ethane is mixed with 107. g of oxygen. Calculate the minimum mass of ethane that could be left over by the chemical reaction. Be sure your answer has the correct number of significant digits.

Answer 1

2C2H6 + 7O2 ==> 4CO2 + 6H2O
mols ethane = grams/molar mass = approx 0.0.57 but you should confirm this and all of the others that follow because I estimate.
mols O2 = 107/32 = 3.34

Now convert mols ethane to mols CO2. That's 0.57 x (4 mols CO2/2 mols C2H6) = 0.57 x 2 = 1.13
Do the same for O2. That's 3.34 x (4 mols CO2/7 mols O2) = 1.9
I have news for you. The limiting reagent is ethane so none of it will be left over. 0.00 is the correct answer although the problem makes it sound as if O2 is the limiting reagent.