Here's why:
* Salt is an ionic compound: This means it's already in a stable state with strong electrostatic bonds between the sodium (Na+) and chloride (Cl-) ions.
* Heat can cause physical changes: Heat will cause the salt to melt and then vaporize, but it won't change the chemical composition of NaCl.
Think of it like this: Heating salt is like heating ice. The ice melts into water, but it's still H2O. Similarly, heating salt changes its state, but it remains NaCl.
