"Gold coins don't quench fires on your world, do they?"
No, they don't, because gold is formed from ball like clusters of energized and illumined earth element. Fire element introduced to gold lubricates it and causes it to soften, restores its energy (fire is the most likely of the four elements to resist the downward pull of the cascade), and drives off earth elemental structures that are more opposed to fire. It is the precence of this trapped fire within gold which makes gold so resistant to earth elements natural opposing element (water), and which causes it to be so malable.
Gold is an effacious element in overcoming water, or in allying with fire, but certainly couldn't drive away fire elemental particles.
This is basic alchemy that any third year student ought to know.
Water on the other hand drives away fire elemental particles (fire atoms if you would), and is itself driven back into the cascade by fire in a mutual destructive fashion with steam being a temporary byproduct. Note that an Alchemist measuring water in a closed chamber putting out a torch would find, unlike in this world, that the product was not necessarily of equal weight. Unlike this world, the exchange of particles between universes is a phenomon measureable on a macro scale. In this universe, matter and energy are not conserved. Also note that an alchemist conducting a phylgiston expertment by grinding a cannon in a tub of water would - unlike this world - find that the ammount of fire elemental particles released into the water _did_ drop over time.
The point of this being that the ability to make gunpowder and nitroglycerin in this world and otherwise do chemistry does not guarantee that you can do alchemy in my world, despite some superficial resemblances between the two. Also don't assume that experiments are going to work exactly the same.