Answer:
[tex]\Delta _rH=-802.2kJ/mol[/tex]
Explanation:
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In this case, according to the given chemical reaction, it is possible to calculate the enthalpy change of the reaction via:
[tex]\Delta _rH=\Delta _fH_{CO_2}+2\Delta _fH_{H_2O}-\Delta _fH_{CH_4}[/tex]
Since the enthalpy of formation of oxygen is 0. Thus, given the enthalpies of formation of gaseous carbon dioxide and water, we obtain:
[tex]\Delta _rH=(-393.5kJ/mol)+2(-241.8kJ/mol)-(-74.9kJ/mol)\\\\\Delta _rH=-802.2kJ/mol[/tex]
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