I'm a maths tutor who has been roped into helping out with some chemistry for a secondary student (Year 9, i.e. about 14-15 years of age). My chemistry knowledge is a touch rusty (pun intended).
The question is to give examples of things which are both a physical change of state and a chemical reaction.
Does dissolving metal in a strong acid count as a physical change of state? E.g. metallic iron reacts with a strong acid, changing to a Fe2+ or Fe3+ ion. That's certainly a chemical reaction, but does that count as a change of physical state? Ions in solution doesn't seem to fit into the traditional solid/liquid/gas triad.
(For that matter, when a non-ionic molecule like glucose is dissolved in water, what physical state is it in? It's not a suspension, its not a liquid or a gas.)
If this is not a good example, what would be?
Thanks in advance.