Prestidigitation can alter color, taste, stickiness. Keltham has now verified that Prestidigitation can modify acidity and basicness in order to modify the reaction of vinegar with wood ash (lye). He's previously verified that Prestidigitation can produce temporary magnetism but only for so long as Keltham is concentrating, and even that he can get a material to reject a magnetic field using Prestidigitation.
All of this is of a kind with the shapes of the electron orbitals, the potential energy surfaces that determine possible reactions and reaction rates.
Prestidigitation should definitely be a sort of thing that can break the rules of chemistry. They should be able to make Element-20 'calcium' behave like Element-23 'vanadium' for purposes of turning it into something that behaves like vanadium oxide, without Keltham needing to somehow figure out which Golarion metal is 'vanadium'. Though vanadium oxide is donating oxygen molecules within the chemical reaction, so the oxygen part ought to be real.
There could maybe be a way to directly Prestidigitate sulfur dioxide to quickly react with oxygen at high temperatures, and turn into sulfur trioxide without need of a vanadium catalyst, if they really knew what they were doing. There may be, conceptually speaking, something sulfur dioxide could taste like, which would make it react more easily with oxygen and slide down the exothermic gradient to sulfur trioxide.
Keltham is guessing that energy is probably conserved, even in the presence of Prestidigitation, which means that they probably can't do very much work of a form 'make this very tight binding loose' because it should properly take energy to shake loose of a binding like that. But even small changes at the potential energy surfaces can do a lot to eliminate reaction barriers.
...though there's already hints that you need to be able to... sort of understand that stuff, or visualize it, on some level, to get Prestidigitation to know what it is you want it to do?
How are people doing on that.