posted by Jake .
When 20.0 g C2H6 and 60.0 g O2 react to form CO2 and H2O, how many grams of water are formed?
balance the equation:
2C2H6+5O2>>4CO2 + 6H2O
figure the moles in 20 g ethane, and moles in 60 grams O2.
Notice, that you need 2.5x moles O2 as moles ethane. Do you have that much? If more, then ethane is the limiting reactant. If not, thenO2 is limiting.
so if ethane is limiting, then you get 3 times the moles of water that you have of ethane, if O2 is limiting, you get 6/5 the moles you have of O2.