What's in a chemical equation?

Question

For example, (aq) and (s). What do they mean?

Answer 1

(aq) mean aqueous or in a water solution like Na+(aq) means sodium ion in water

(s) mean a solid like Ag(s) is silver metal (solid)

Answer 2

(aq) = aqueous - a solution were the solvent is water.
(s) = Solid
Also
(l) = liquid
(g) = gas
For example.
CaCO3(s) = CaO(s) + CO2(g)
HCl(aq) + NaOH(aq) = NaCl(aq) + H2O(l)
It states the physical state/condition of the reactants and products.