Combustion Reaction - Writing and Balancing

[Michael_Johanis_2K]

For 8.93, we have to write the combustion reaction for C6H6 (l).

The solutions manual says:
C6H6 (l) + 7.5 O2 (l) ----> 6CO2 (g) + 3H2O (l)


1) Why is 3H2O a liquid? Shouldn't all the products in combustion reactions be gases?
2) Why is 7.5 the coefficient for O2? Shouldn't everything be in whole numbers? I think we should double everything to make all the coefficients whole numbers.

[Theresa Dinh 3F]

H2O is normally a liquid. Especially since the combustion reaction appears to be just two liquids reacting with each other, which means that most likely they are not heating up enough to react. O2 liquid is usually found in only extremely cold temperatures.

You can double the equation if needed, but that would mean you need to double the delta h of the reaction as well. This gives the equation in simplified form.

[danae_blodgett_1H]

Can other products be liquid as well, or only H2O?