
Fundamental units: why kelvin and mole?
Can't we just define (derive) temperature from the internal energy of an ideal gas?
Consider: deltaU = 3/2 k_B deltaT
We could define the kelvin as: A temperature increase of 1K is the increase that raises the average energy per particle by 3/2 J, with K being dimensionally the same as J.
Why then do we have K as a fundamental unit?
The case against mol being a _fundamental_ unit is just coz its a really useful number in Chemistry, at the end of the day it's just a gigantic number-fundamentally no different than say "dozen".