starpaste

the thing is that the C--O is not being broken to make to C==O bond, because I am comparing an intermediate to the product it makes, so only electrons are being shifted in the mechanism. wouldn't it be the value of c==o - c--o?

For the equation change in enthalpy = bonds broken - bonds made. What if the compound makes a double bond. Meaning in the reactants there is a C--O bond, in the product it becomes C=O, do i add for bonds made the value for a single C-O bond (since 1 C--O bond already exists) or the value for a C=O (the final product)?

but doesnt the double bond pull in the electrons from oxygen making it less polarizable ? thanks!

I learned about what makes a good nucleophile. But take a sample case RCO2H is the carbonyl oxygen more nucleophilic or the oxygen attached to the proton? - they both have resonance (??)