I'm an organic chemist?

 

There is an amusing pattern in many forms of learning: "U-shaped development."

You learn a little something and are good (the real Newbie's Luck?), you learn

more and your skills decline, then finally you get better again. Perhaps here is similar:

you learn to calculate (manually) the standard enthalpy of formation (\Delta H_f), then 

in quantum/computational chemistry you forget, then you need to calculate/report it for

a collaborative work with synthetic chemists and learn it better...