* Enthalpy of Formation: This refers to the change in enthalpy when one mole of a compound is formed from its constituent elements in their standard states at 298K and 1 atm.
* The Reaction: The reaction you provided: CO2(g) + H2 → H2O + CO is a combustion reaction, not a formation reaction.
Here's why it's a combustion reaction:
* Reactants: Carbon dioxide (CO2) is a product of combustion, not a reactant in the formation of a compound. Hydrogen gas (H2) is a fuel that is being burned.
* Products: Water (H2O) and carbon monoxide (CO) are products of the incomplete combustion of a fuel.
To represent an enthalpy of formation, you would need a reaction that:
* Forms one mole of the desired compound.
* Uses only the constituent elements in their standard states as reactants.
Example:
The enthalpy of formation of carbon dioxide (CO2) would be represented by:
C(s) + O2(g) → CO2(g)
