Первая картинка
A5 Б3 В2 Г2
дано
m(Cu) = 12 g
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m(CuO)-?
2Cu+O2-->2CuO
M(Cu) = 64 g/mol
n(Cu) = m/M = 12 / 64 = 0.1875 mol
2n(Cu) = 2n(CuO) = 0.1875 mol
M(CuO) = 80 g/mol
m(CuO) = n*M =0.1875 * 80 = 15 g
ответ 15 г
Mn+H2SO4--->MnSO4+H2
MnSO4+2NaOH=Mn(OH)2+Na2SO4
Mn(OH)2 + 2O2 + 4H2O = 2Mn(OH)4
2Mn(OH)2 + 2KMnO4 = K2MnO4 + 3MnO2 +2H2O
MnO2+4HCl=MnCl2+Cl2+2H2O