I'm a high school student doing a project where we need to identify chemicals and one of the substances had a very unique change when heated.
Before heating it was an extremely fine, flour-like white powder. I placed it on a hotplate at 350 degrees Celsius in its solid form and it "boiled off", I presume a hydrate evaporating. Before the hydrate appeared to evaporate, the powder had small pink dots appear all over it. This also happened when exposed to $\ce{NaClO}$ and $\ce{NaOH}$.
Once the temperature was raised to 400 degrees Celsius, the remaining solid turned yellow and then spontaneously caught fire, turning it all black before the fire ran out.
I had ran other tests on this substance, being insoluble in water, ethanol, and hexane. It also produced no apparent flame color.
My initial thought was that this compound was starch, however now that I think about it, it may be an insoluble magnesium compound, due to the lack of flame color? Just curious as to if anyone knows what substances display these properties when heated.
Here is a list of potential substances based off of a predetermined list.
- Aluminum nitrate
- Ammonium chloride
- Ammonium nitrate
- Ammonium sulfate
- Barium acetate
- Barium nitrate
- Barium oxide
- Barium sulfate
- Calcium carbonate
- Calcium chloride
- Calcium oxide
- Calcium nitrate
- Calcium sulfate
- Iron(II) sulfate
- Iron(III) sulfate
- Lauric acid
- Lithium carbonate
- Lithium nitrate
- Magnesium carbonate
- Magnesium chloride
- Magnesium hydroxide
- Magnesium oxide
- Magnesium sulfate
- Potassium bromate
- Potassium carbonate
- Potassium chloride
- Potassium iodide
- Potassium metabisulfite
- Potassium nitrate
- Potassium persulfate
- Potassium phosphate
- Potassium sodium tartrate
- Potassium thiocyanate
- Sodium acetate
- Sodium bisulfate
- Sodium borate
- Sodium carbonate
- Sodium citrate
- Sodium chloride
- Sodium fluoride
- Sodium nitrate
- Sodium nitrite
- Sodium oxalate
- Sodium sulfate
- Sodium sulfite
- Sodium thiosulfate
- Starch
- Strontium carbonate
- Strontium hydroxide
- Strontium nitrate
- Sucrose
- Tin(II) chloride
- Urea
- Zinc nitrate
- Zinc sulfate
Of these, as stated earlier, an Mg compound (due to insolubility) or starch is most likely.