Question

Hydrogen and methanol have both been proposed as alternatives to hydrocarbon fuels. Part A Write balanced reactions for the complete combustion of hydrogen. Express your answer as a chemical equation. Identify all of the phases in your answer. 2H2 (8)+O2(g)+2H2O(1) Submit Previous Answers Request Answer * Incorrect; Try Again Part B Use standard enthalpies of formation to calculate the amount of heat released per kilogram of the fuel. Express your answer using four significant figures. DAXO amount of heat released = 143000 kJ/kg Submit Previous Answers Request Answer x Incorrect; Try Again Part Write balanced reactions for the complete combustion of methanol. Express your answer as a chemical equation. Identify all of the phases in your answer. 2CH3 OH(I)+302 (8) 2002 (g) + 4H2O(1) Submit Previous Answers Request Answer * Incorrect; Try Again Part D Use standard enthalpies of formation to calculate the amount of heat released per kilogram of the fuel. Express your answer using four significant figures. AXO amount of heat released = 726 kJ/kg Submit Previous Answers Request Answer * Incorrect; Try Again Part E Which fuel contains the most energy in the least mass? Hydrogen Methanol

Answer 1

Solni A The reaction can be written as 2H2(g) + O2(g) → 2 H20 (1) B) Now the enthalpy of the combustion of the given reaction ΔΗ ηχης Στηρ ΔHP (Produ) - Σδη Η κριτική) = [2X AF H20 (1) 4 (2 X DH f H2 (8) + 1 (DHP02(8) 77 - 2x (-285-8)k] - [ 2x (0) H0] kJ = -571.6 kJ Heat is released when 4g of hydrogen was combusted in the presence of air. So, to liberak the amount of energy for 1kg of hydrogen the requined fuel us 1x 2000 x 5716 = 142900 kilky 3 c) The reaction iss 2 CH3 Olt (1) + 302 (g) - 2 C02(g) +4 1420 (1) The enthalpy of Combustion of the above reaction. Shoxna nnx Eoli Cpoodetsy) o x Ente reactant) 1 4 x Alte H20 (1) + 2xDHE C02 (8)}-2(2xAHpcl3 OH CD+360460) = [ 2% (-393.5) + 4X(-285.8)JW1-C2X(-238·6) +3 xOTkJ = - 1453KJ this amount of heat was released when 64°0729 of methanol us Combused in the presence of an So for kg of the hydrogen fuel amount of energy - 1x 1000 x 145.072 22677.613 kJ/ky

So from the above calculation if us clear that the hydrogen gas contains more energy and also feast mass then Methanol