[kemilss]

Hey,

    I'm doing some studying (I don't have a teacher for this course I am taking) and I have a question.  Basically, when asked "List these fuels in order of increasing enthalpy of formation", one solution in my textbook goes from lowest to highest ( e.g. - 512, -350 , -200, -50 ) and then about 40 questions later another question asks "List the above standard molar enthalpies of combustion of propane from lowest to highest" and the solution to this question goes the other way ( -1500, -2000, -2500, etc... ).  So now I'm confused.

As I understand it, Enthalpy is the measure of energy in the system.  I got the first question right, and the other one wrong.  I simply considered a lower negative value, to mean lower enthalpy.  However, I could understand how a lower negative number could actually mean a higher enthalpy, if we are talking about higher potential difference, or the fact that a lower negative number just communicates that the products "lost" a larger number, but the system still gained that number.

Anyone follow me!?