Classify the following reactions, based on the changes happening at an atomic/molecular level.
1. AlF3(aq) + 3H2O(l) ? Al(OH)3(s) + 3HF(aq)
2. BaCl2(aq) + Na2SO4(aq) ? BaSO4(s) + 2NaCl(aq)
3. Ca(OH)2(s) ? CaO(s) + H2O(g)
4. Ca(s) + 2H2O(l) ? Ca(OH)2(aq) + H2(g)
5. CaO(s) + CO2(g) ? CaCO3(s)
6. Cl2(aq) + 2NaI(aq) ? 2NaCl(aq) + I2(aq)
7. Cu(s) + 2AgNO3(aq) ? Cu(NO3)2(aq) + 2Ag(s)
8. Fe(s) + 2HCl(aq) ? FeCl2(aq) + H2(g)
9. H2SO3(aq) ? H2O(l) + SO2(g)
10. 2HgO(s) ? 2Hg(l) + O2(g)
11. KOH(aq) + HNO3(aq) ? KNO3(aq) + H2O(l)
12. 4Li(s) + O2(g) ? 2Li2O(s)
13. Na2S(aq) + 2HCl(aq) ? 2NaCl(aq) + H2S(g)
14. NH3(g) + HCl(g) ? NH4Cl(s)
15. NiCO3(s) ? NiO(s) + CO2(g)
16. P4(s) + 10F2(g) ? 4PF5(g)