Which event represents a chemical change?

1 The first one would be using word/chemical equations, as you mentioned. However, with state symbols.

For example,
NaOH(aq) + HCL(aq) ---> NaCl(aq) + H2O(l)

Aqueuos Sodium hydroxide + Dilute Hydrochloric Acid ---> Aqueuos Sodium Chloride + Water

#2 The second one would be an experiment. You can try this simple experiment:

1. Pour a few drops of aqueous sodium hydroxide to 2cm^3 of aqueous iron(ll) nitrate.
2. A green precipitate would form.

That represents the chemical reaction between aqueous iron(ll) nitrate and aqueous sodium hydroxide to form iron(ll) hydroxide.
You can use diagrams to show the experiment procedure.

Well i've run out of ideas because the things i listed is what i have learnt so far. I hope that i helped in a way or another. Good luck! (:

It's a

It conforms what ever surface its in.