3) \(C_xH_yO_z+\left(x+\dfrac{y}{4}-\dfrac{z}{2}\right)O_2\xrightarrow[]{t^o}xCO_2+\dfrac{y}{2}H_2O\)
4) \(8Fe_3O_4+37H_2SO_4\rightarrow12Fe_2\left(SO_4\right)_3+H_2S+36H_2O\)
5) \(8Al+30HNO_3\rightarrow8Al\left(NO_3\right)_3+3NH_4NO_3+9H_2O\)
6) \(8Fe_3O_4+74HNO_3\rightarrow24Fe\left(NO_3\right)_3+NH_4NO_3+35H_2O\)
7) \(2Fe_xO_y+\left(6x-2y\right)H_2SO_4\rightarrow xFe_2\left(SO_4\right)_3+\left(3x-2y\right)SO_2+\left(6x-2y\right)H_2O\)
8) \(2Al+Ca\left(NO_3\right)_2+8HCl\rightarrow2AlCl_3+CaCl_2+2NO+4H_2O\)