8.113

[Leah Savage 2F]

8.113 says: Water gas is an inexpensive, low-grade fuel that can be made from coal. (a) Is the production of water gas exothermic or endothermic? The reaction is C (s) + H2O (g) --> CO (g) + H2
(b) Calculate the enthalpy change for the production of 200. L of hydrogen at 500. Torr and 65 C by this reaction.

Can someone explain why the solutions manual uses 0 for the value of the enthalpy of formation for C(s) to find the enthalpy of the reaction? Isn't the standard state of carbon (gr)?

[Andrea Grigsby 1I]

what does the state (gr) mean?

[torieoishi1A]

the state gr means graphite. It is the most stable form of carbon under standard conditions.

[Austin Ho 1E]

I think in this question when they say C(s) they're specifying that it's solid carbon and not necessarily graphite. Therefore, its formation enthalpy is 0.