7-39
1) PbO2+Al - Al2O3+ Pb
Коэфициенты
Pb(степень окисления +4)------Pb(0) 3
Al(0)-----Al(+3) 4
3PbO2+4Al = 2Al2O3 + 3Pb
2)H2S +O2 - S+ H2O
S(-2)------S(0) 2
O2(0)------O(-2) 2
2H2S +2O2 = 2S+ 2H2O
3)KClO3+ S - SO2+KCl
Cl(+5)------Cl(-1) 2
S(0)-----S(+4) 3
2KClO3+ 3S=3SO2+2KCl
4)H2SO4 + Na- Na2SO4+H2S+H2O
Na(0)-----Na(+1)
S(+6)-----S(-2)
10H2SO4 + 16Na = 8Na2SO4+2H2S+8H2O
7-40
1)V2O5+Al- Al2O3+V
V(+5)----V(0)
Al(0)-----Al(+3)
3V2O5+10Al=5Al2O3+6V
2)NH3+O2-N2+H2O
O2(0)---O(-2) 3
N(-3)-----N(0) 2
4NH3+3O2 = 2N2+6H2O
3)HNO3+Cu--Cu(NO3)2+NO2+H2O
Cu(0)---Cu(+2)
N(+5)---N(+4)
4HNO3+1Cu = 1Cu(NO3)2+2NO2+2H2O
7-41
1)Fe2O3+H2 - H2O+Fe
Fe(+3)----Fe(0)
H2(0)------H(+1)
3Fe2O3+9H2 = 9H2O+6Fe
2)Na2SO3+O2- Na2SO4
S(+4)----S(+6)
O2(0)----O(-2)
2Na2SO3+1O2 = 2Na2SO4
3)Zn+H2SO4 - ZnSO4 +S+H2O
Zn(0)---Zn(+2)
S(+6)-----S(0)
3Zn+4H2SO4 = 3ZnSO4 +1S+4H2O