4.7 - does water result as a gas or vapor in combustion? [ENDORSED]

[Sue Bin Park 2I]

in part a of the question, the answer key's result requires you to assume that water vapor is produced in the reaction (to get the right delta n of gaseous products). however, in part b to get the provided solution you have to use the enthalpy of formation of liquid water to get the "correct" answer. is this a discrepancy in the book? (i'm going off of the back of the book). or do i not know some convention about combustion rxns?

[Chem_Mod]

Under standard conditions water is a liquid.

Assume standard conditions apply unless the information given states otherwise.