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What is a compound that changes colour when heated but doesn't actually undergo a chemical reaction? It just changes colour and then as it cools it returns to the original colour. I'm having a mental blank. I haven't done this one for a few years and despite searching multiple words and phrases I can't find it on here...
Thanks and I hope you're all off to a good start this year
Used silica gel will change colour on heating. Hydrated CuSO4 will turn from blue to white on heating due to water loss. I can't think of something that will change back on cooling apart from thermochromic dyes which I'm pretty sure schools don't usually have on hand. Good luck!
I did some further googling after posting here (I had done a little bit before asking) and found that Iron (III) oxide turns black at before 500deg then back to reddish brown at room temp so I'm going to give that a go.... I can remember years ago Smiley brought it up (sometime between 2007 and 2013 when I was a lab assistant previously) but that conversation may have been deleted.
