1. In the balanced equation, 1 mole of C3H8 reacts with 5 moles of O2 to produce 3 moles of CO2 and 4 moles of H2O. Therefore, if we have 12.0 moles of C3H8, we need 5*12.0 = 60.0 moles of O2 to react completely.
2. In the balanced equation, 1 mole of C3H8 reacts with 5 moles of O2 to produce 3 moles of CO2 and 4 moles of H2O. Therefore, if we have 13.5 moles of O2, we would produce 4*13.5 = 54.0 moles of H2O
3. In the balanced equation, 1 mole of C3H8 reacts with 5 moles of O2 to produce 3 moles of CO2 and 4 moles of H2O. If we know that we have 1.35 moles of CO2, we can use this relationship to find the amount of H2O produced. Since the ratio of CO2 to H2O is 3:4, for every 3 moles of CO2 produced, we would produce 4 moles of H2O. Therefore, if 1.35 moles of CO2 are produced, we can divide 1.35 by 3 to find the number of moles of H2O produced, which is 1.35/3 = 0.45 moles of H2O.