I guess I was just trying to refer to the transition state with the enzyme vs. the transition state without the enzyme, sorry if I was unclear. But thank you, that diagram actually helped a lot, all of the ones in my biology textbook are a lot more basic.
So, I know that enzymes are not consumed in the reactions they catalyze, and that they catalyze these reactions by lowering the activation energy. So, in an uncatalyzed reaction, more energy is required to "kick off" the reaction, resulting in the same overall change in free energy. I'm just...
So, is enthalpy just a term defined this way in order to simplify the "energy bookkeeping" for constant pressure reactions? I think I saw somewhere that the (+ PV) accounts for the energy required to push the atmosphere out of the way for the volume, which cannot be considered internal energy...
Going from:
E = q + w
To:
H = E + (PV)
I'm confused as to why you add the product of the pressure and volume of the system to the internal energy to get enthalpy. Is it just because "that's what enthalpy is defined as"? I think I understand that when holding pressure constant, the (PV)...