posted by alex on .
2H2(g) + O2(g) = 2H2O (l)
Calculate the volume of Hydrogen gas at STP required to produce an amount of energy equivalent to that produced by the combustion of a gallon of octane. The density of octane is 2.66 kg/gal, and its standard enthalpy of formation is -249.9 kJ/mol.
This problem requires many steps, and I will just outline the process of solution.
(1) Each mole of H2O formed will release 57.8 kcal if carried out at STP with liquid H2O as the product. One mole of H2 will be consumed in the process. The actual process will have H2O (g) as a product, with the result that less usable heat is usually generated.
(2) Write the balanced reaction for the complete oxidation of octane.
(3) Use your stated heat of formation of octane (C8H18), and those of H2O and CO2, to determine the heat of reaction per mole of octane burned. Assume liquid H2O and gaseous CO2 as products
(4) Compare the heats of reaction per mole of H2 and mole of CO2 burned
(5) Convert 1 gallon of octane to moles and grams.
(6) Compute the heat release from burning one gallon of octane
(7) Compute the number of moles of H2 needed to release the same amount of heat
(8) Convert (7) to STP volume of H2
no! im taking a timed quiz!!!
is it 2.25 L??