posted by Annabelle .
From the following information, calculate the standard change of enthalpy for the combustion of coal.
C + O2 -> CO2
COMPOUND HEAT OF FORMATION
carbon dioxide -393.5
water (l) -285.9
dHrxn = (n*dHf products) - (n*dHf products)
So I would assume that the answer would be (-393.5)-(0)= -393.5
However, the problem lists the compound heat of formation for water also, which makes me think I have the wrong balanced equation up top, but at the same time no type of coal is specified, so there is no way to know the organic components it is made up of. Is this correct?