Write balanced reactions for the complete combustion of hydrogen. Express your a

ID: 918727 • Letter: W

Question

Write balanced reactions for the complete combustion of hydrogen.

Express your answer as a chemical equation. Identify all of the phases in your answer.

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.

Part C

Write balanced reactions for the complete combustion of methanol.

Express your answer as a chemical equation. Identify all of the phases in your answer.

Part D

Use standard enthalpies of formation to calculate the amount of heat released per kilogram of the fuel.Part D

Express your answer using four significant figures.

Part E

Which fuel contains the most energy in the least mass?

Part F

How does the energy of these fuels compare to that of octane (C8H18)?

Express your answer using four significant figures.

Hydrogen Methanol

2H2(g) + O2(g) ------> 2H2O(l)

delta Hrkn = 2*(delta Hf H2O) - 2*(delta Hf H2) - (delta Hf O2) = -285.8*2 - 0 - 0 = -571.6 kJ

Thus, energy released by burning 2 moles i.e 4 g of H2 = 571.6 kJ

therefore energy released by burning 1000 g of H2 = 142900 kJ

CH3OH(aq) + (3/2)O2(g) ----------> CO2(g) + 2H2O(l)

heat released by combustion of 1 mole i.e 32 g of methanol = 726 kJ

Hence heat released by burning 1000 g of methanol = 726*1000/32 = 22687.5 kJ

Clearly H2 has more energy in least mass

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