Question

Methane is the major component of natural gas. The standard molar enthalpy of formation of methane CH4 is -74.9 kJ/mol. For the balanced reaction equation of methane use:

CH4 + 2O2 --> CO2 + 2H2O.

All the chemicals in this reaction are gases. What is the enthalpy change of this reaction in kJ/mol?

Answer 1

`\Delta _rH=-802.2kJ/mol`

Step-by-step explanation:

Hello!

In this case, according to the given chemical reaction, it is possible to calculate the enthalpy change of the reaction via:

`\Delta _rH=\Delta _fH_(CO_2)+2\Delta _fH_(H_2O)-\Delta _fH_(CH_4)`

Since the enthalpy of formation of oxygen is 0. Thus, given the enthalpies of formation of gaseous carbon dioxide and water, we obtain:

`\Delta _rH=(-393.5kJ/mol)+2(-241.8kJ/mol)-(-74.9kJ/mol)\\\\\Delta _rH=-802.2kJ/mol`

Best regards!