With regards to your solution, it doesn't make sense to me. From both high school chemistry and just a reasonable assumption, it would be fair to say that the state of the chemicals depends on the temperature of the room, and not anything else. While the liquid can thusly be explained away by assuming the gas heater was used around the liquid, making that region warmer and thus the chemical(s) went through condensation, becoming liquid, this is only under the assumption that Normallium and Fatallium were mixed. I still see no evidence for it. One minute after the 'proof', the game acknowledges it is not a real proof. But the game should somehow acknowledge the liquid, and somehow explain it away.

I feel it is bad writing to not acknowledge that in any way, and to ask the player to find a proof for something but then the desired answer isn't actually a proof, and not explain away a possible flaw in the system.