textbook problem 4D.15

[Katie Bart 1I]

In this problem, where do you obtain the information you need in order to write the three different balanced equations that are written in the solutions manual?

[Skyllar Kuppinger 1F]

Those are combustion equations. The combustion of a hydrocarbon is: the hydrocarbon + oxygen = water + carbon dioxide. The combustion of just hydrogen is hydrogen + oxygen = water. So you write those combustion equations and balance them by putting the right coefficients in front of each molecule.

[Caitlyn Tran 2E]

In this problem, they give you the enthalpy for the combustion of three different compounds. In combustion, you know that the compound will react with oxygen to produce carbon dioxide and water vapor. Once you balance them, this is how you get the three equations. From there, you can use Hess's Law to solve the problem. Hope this helps!