\(4P+5O_2\rightarrow\left(t^o\right)2P_2O_5\\ Ca\left(OH\right)_2+CO_2\rightarrow CaCO_3\downarrow+H_2O\\ 2K+2H_2O\rightarrow2KOH+H_2\uparrow\\ Fe+2HCl\rightarrow FeCl_2+H_2\uparrow\\ 2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\uparrow\\ Fe+S\rightarrow\left(t^o\right)FeS\\ 2Al\left(OH\right)_3\rightarrow\left(t^o\right)Al_2O_3+3H_2O\\ 2HgO\rightarrow\left(450^oC-500^oC\right)2Hg+O_2\uparrow\\ CuCl_2+2KOH\rightarrow Cu\left(OH\right)_2\downarrow+2KCl\\ Cu\left(OH\right)_2\rightarrow\left(t^o\right)CuO+H_2O\)
1. `4P + 5O_2 -> 2P_2O_5`
2.`Ca(OH)_2 + CO_2 -> CaCO_3 \downarrow + H_2O`
3. `2K +2 H_2O -> 2KOH + H_2 \uparrow`
4. `Fe + 2HCl -> FeCl_2 + H_2 \uparrow`
5. `2Al + 3H_2SO_4 -> Al_2(SO_4)_3 + 3H_2 \uparrow`
6. `Fe + S -> FeS`
7. `2Al(OH)_3 -> Al_2O_3 + 3H_2O`
8. `2HgO -> 2Hg + O_2 \uparrow`
9. `CuCl_2 + 2KOH -> Cu(OH)_2\downarrow + 2KCl`
10. `Cu(OH)_2 ->CuO + H_2O`