Problem: If hydrogen were used as a fuel, it could be burned according to the following reaction: H2(g)+1/2 O2(g)→H2O(g).A) Use average bond energies to calculate ΔHrxn for this reaction. (Answer for this part is -243 kJ/mol but I was unable to get this number when I tried solving it.)B) Use average bond energies to calculate ΔHrxn for the combustion of methane (CH4).C) Which fuel yields more energy per mole: hydrogen or methane?D) Per gram: hydrogen or methane?

FREE Expert Solution

To calculate the ΔH°rxn using bond energies, we’re going to use the following equation:

H°rxn=H°reactants-H°products


Part A. 


Balanced Reaction: H2(g) + 1/2 O2(g) → H2O(g)

*always make sure that the given reaction is balanced


Draw the structure of each compound.

Reactants:

H2(g): 

O2(g):

Products:

H2O:

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Problem Details

If hydrogen were used as a fuel, it could be burned according to the following reaction: H2(g)+1/2 O2(g)→H2O(g).

A) Use average bond energies to calculate ΔHrxn for this reaction. (Answer for this part is -243 kJ/mol but I was unable to get this number when I tried solving it.)

B) Use average bond energies to calculate ΔHrxn for the combustion of methane (CH4).

C) Which fuel yields more energy per mole: hydrogen or methane?

D) Per gram: hydrogen or methane?

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