Question

How many C2H6+O2 would you need to be equal to how many CO2+H20

Answer 1

Balance the combustion of ethane (C2H6):

C2H6 + (7/2) O2 → 2 CO2 + 3 H2O

So 1 mole (or 1 molecule) of C2H6 needs 3.5 moles (or 3.5 molecules) of O2 to produce 2 moles (2 molecules) of CO2 and 3 moles (3 molecules) of H2O.

To avoid fractions, use whole numbers:

2 C2H6 + 7 O2 → 4 CO2 + 6 H2O.