[docteurdeno]

I'm planning to investigate the factors that affect the combustion and formation enthalpies on different organic compounds as a part of my chemistry project. I have two independent variables: the carbon chain length of a compound, and the functional group. I have compiled the combustion and formation enthalpies of 15 different compounds as shown here: https://imgur.com/a/slmuBco

I have then plotted these data on graphs. (Carbon chain length/enthalpy)
Combustion: https://imgur.com/a/huoI3eh
Formation: https://imgur.com/a/e3ZDnzW

I don't quite understand why the combustion enthalpy follows a trend where carboxyl> carbonyl> hydroxyl but the formation enthalpy follows a trend where carbonyl> hydroxyl> carboxyl. Also, 1-propanol seems to deviate from the general trend, and I don't know why. If you can help me out, I would really appreciate it.

[sjb]

no need to cross post, locked here