• Part A Enter a balanced reaction for the complete combustion of hydrogen. Express your answer as a chemical equation. Identify all of the phases in your answer. 2H2(g)+ O2(g)+2H20 (g) Submit Previous Answers v Correct The balanced combustion equation is 2H2(g) + O2(g)–→2H2O(g) • Part B Use standard enthalpies of formation to calculate the amount of heat released per kilogram of hydrogen fuel. Express your answer using four significant figures. amount of heat released = 1.418×105 kJ/kg Previous Answers Submit All attempts used; correct answer displayed The enthalpy of formation of water can be used to calculate the amount of energy released per kilogram of fuel. Since only water is present in a nonstandard state, the enthalpy for the reaction is equal to the enthalpy of formation of water. Thus 1 mol 0.002016 kg AH H20 (kJ/mol) × where 0.002016 kg/mol is the molar mass of hydrogen gas. • Part C Enter a balanced reaction for the complete combustion of methanol. Express your answer as a chemical equation. Identify all of the phases in your answer. 2CH3OH(1)+ 302(g}>2CO2(g)+ 4H20(g) Submit Previous Answers v Correct The balanced combustion equation is 2CH3OH(1) + 302(g) → 2CO2(g) + 4H20(g) , Part D Use standard enthalpies of formation to calculate the amount of heat released per kilogram of methanol fuel. Express your answer using four significant figures. amount of heat released = 2,267x104 kJ/kg Submit Previous Answers v Correct The enthalpies of formation of carbon dioxide, water, and methanol can be used to calculate the amount of energy released per kilogram of fuel as follows: AHfxn = npA Hf(products) – nrA Hf(reactants) [(AH? CO2 + 2(A HỆ H20 ) – AH? CH3OH] (kJ/mol) Once you have the enthalpy change for the reaction, divide by the molar mass of the fuel, methanol, in kg/mol to find the heat released. , Part E Which fuel contains the most energy in the least mass? hydrogen methanol Previous Answers Submit v Correct Using the results from Parts B and D of the question. Hydrogen contributes almost an order of magnitude more energy per kilogram of mass than does methanol. • Part F To compare the energy of these fuels to that of octane (CgH19 , calculate the energy released per kilogram of octane. Express your answer using four significant figures. kJ/kg amount of heat released by octane =