3NaOH(изб.) + FeCl3 --> Fe(OH)3 осадок + 3NaCl
1) m(в-ва) FeCl3= 200* 0.05 =10 г
2) n(FeCl3)= m/Mr= 10/162.5=0.062 моль
3) по уравнению n(FeCl3)=n(Fe(OH)3)=0.062 моль
4) m(Fe(OH)3)=n*Mr= 0.062*107=6.58г
Ответ: 6.58 г
3.
дано
m(CL2) = 17.75 g
---------------------
m(FeCL2)-?
17.75 X
2Fe+3CL2-->2FeCL3 M(CL2) = 71 g/mol , M(FeCL3) = 162.5 g/mol
3*71 2*162.5
X = 17.75 * 325 / 213 = 27.08 g
ответ 27.08 г
4.
дано
m(H3PO4) =19.6 g
NaOH
---------------------
m(Na3PO4)-?
19.6 X
H3PO4+3NaOH-->Na3PO4+3H2O
98 3*40
M(H3PO4) = 98 g/mol M(NaOН) =40 g/mol
X = 19.6*120 / 98 = 24 g
ответ 24 г
5.
дано
m(HCL)= 9.125 g
+Fe
----------------------------
m(FeCL2)-?
9.125 X
2HCL+Fe-->FeCL2+H2 M(HCL)= 36.5 g/mol M(FeCL2) =127 g/mol
2*36.5 127
X =9.125*127 / 73 = 15.875 g
ответ 15.875 г
ZnSO4+K2S-->K2SO4+ZNS
ZN+SO4+2K+S-->2K+SO4+ZnS
ZN+S-->ZNS
2Al + 3H2SO4 = Al2(SO4)3 + 3H2
4Al + 3O2 = 2Al2O3
Al2O3 + 6HCl = 2AlCl3 + 3H2O
AlCl3 + 3NaOH = Al(OH)3 + 3NaCl
2Al(OH)3 (t)= Al2O3 + 3H2O