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\(a) \\ Fe + H_2SO_4 \to FeSO_4 + H_2\\ Fe_2O_3 + 3H_2SO_4 \to Fe_2(SO_4)_3 + 3H_2O\\ b) \text{Theo PTHH} : \\ n_{Fe} = n_{H_2} = \dfrac{2,24}{22,4} = 0,1(mol)\\ \%m_{Fe} = \dfrac{0,1.56}{8} .100\% = 70\%\\ \%m_{Fe_2O_3} = 100\% -70\% = 30\%\)
\(n_{H_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\\ PTHH:Fe+H_2SO_4\rightarrow FeSO_4+H_2\\ \left(mol\right).....0,1...........................\leftarrow0,1\\ m_{Fe}=0,1.56=5,6\left(g\right)\\ m_{Fe_2O_3}=\Sigma m_{hh}-m_{Fe}=8-5,6=2,4\left(g\right)\\ PTHH:Fe_2O_3+3H_2SO_4\rightarrow Fe_2\left(SO_4\right)_3+3H_2O\\ \left\{{}\begin{matrix}\%m_{Fe}=\dfrac{5,6}{8}.100\%=70\%\\\%m_{Fe_2O_3}=\dfrac{2,4}{8}.100\%=30\%\end{matrix}\right.\)
a)
\(n_{H_2} = \dfrac{3,36}{22,4} = 0,15(mol)\\ n_{Mg} = a\ mol; n_{Fe} = b\ mol\\ Mg + 2HCl \to MgCl_2 + H_2\\ Fe + 2HCl \to FeCl_2 + H_2 \)
Theo PTHH, ta có:
\(\left\{{}\begin{matrix}24a+56b=5,2\\a+b=0,15\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}a=0,1\\b=0,05\end{matrix}\right.\)
Suy ra:
\(\%m_{Mg} = \dfrac{0,1.24}{5,2}.100\% = 46,15\%\\ \%m_{Fe} = 100\% - 46,15\% = 53,85\% \)
b)
\(n_{HCl} = 2n_{H_2} = 0,15.2 = 0,3(mol)\\ \Rightarrow V_{dd\ HCl} = \dfrac{0,3}{1} = 0,3(lít) \)
Đặt :
nMg = a mol
nFe= b mol
mhh = 24a + 56b = 5.2 (g) (1)
Mg + 2HCl => MgCl2 + H2
Fe + 2HCl => FeCl2 + H2
nH2 = a + b = 0.15 (2)
(1) , (2)
a = 0.1
b = 0.05
%Mg = 2.4/5.2 * 100% = 46.15%
%Fe = 100 - 46.15 = 53.85%
nHCl = 2a + 2b = 0.05 * 2 + 0.1*2 = 0.3 (mol)
VddHCl = 0.3/1=0.3 (l)
a, Gọi \(\left\{{}\begin{matrix}n_{Fe_2O_3}=a\left(mol\right)\\n_{ZnO}=b\left(mol\right)\end{matrix}\right.\left(đk:a,b>0\right)\)
\(n_{HCl}=1,5.0,2=0,3\left(mol\right)\)
PTHH:
Fe2O3 + 6HCl ---> FeCl3 + 3H2O
a-------->6a
ZnO + 2HCl ---> ZnCl2 + H2
b----->2b
=> \(\left\{{}\begin{matrix}160a+81b=8,83\\6a+2b=0,3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=0,04\left(mol\right)\\b=0,03\left(mol\right)\end{matrix}\right.\left(TM\right)\)
=> \(\left\{{}\begin{matrix}m_{Fe_2O_3}=0,04.160=6,4\left(g\right)\\m_{ZnO}=0,03.81=2,43\left(g\right)\end{matrix}\right.\)
b, PTHH:
Fe2O3 + 3H2SO4 ---> Fe2(SO4)3 + 3H2O
0,04------>0,12
ZnO + H2SO4 ---> ZnSO4 + H2O
0,03->0,03
=> \(m_{H_2SO_4}=\left(0,12+0,03\right).98=14,7\left(g\right)\)
=> \(m_{ddH_2SO_4}=\dfrac{14,7.100}{30\%}=49\left(g\right)\)
gọi \(x,y\) lần lượt là số \(mol\) của\(CuO\) và \(ZnO\)
số \(mol\) \(HCl\)
\(N=Cm.V=3.0,1=0,3\left(mol\right)\)
lập \(PTHH\) :
\(CuO+2HCl\rightarrow CuCl2+H2O\)
\(x\Rightarrow2x\)
\(ZnO+2HCl\rightarrow ZnCl2+H2O\)
\(y\Rightarrow2y\)
theo \(PTP\) , ta có :
\(2x+2y=0,3\) \(\left(1\right)\)
theo đề ra :
\(mCuO+mZnO=80x+81y=12,1\left(g\right)\) \(\left(2\right)\)
từ \(\left(1\right);\left(2\right)\Rightarrow80x+81y=12,1\left(g\right)\Rightarrow x=0,05\left(mol\right)\)
\(2x+2y=0,3\Rightarrow y=0,1\left(mol\right)\)
\(a,\) \(\%CuO=\dfrac{0,05.80.100}{12,1}=33,06\%\)
\(\%ZnO=\dfrac{0,1.80.100}{12,1}=66,94\%\)
\(b,\) \(CuO+H2SO4\rightarrow CuOSO4+H2O\)
\(0,05\rightarrow0,05\)
\(ZnO+H2SO4\rightarrow ZnSO4+H2O\)
\(0,1\rightarrow0,1\)
\(nH2SO4=0,05+0,1=0,15\left(mol\right)\)
\(mH2SO4=0,15.98=14,7\left(g\right)\)
\(mddH2SO4=14,7:20=73,5\left(g\right)\)
\(n_{H_2}=\dfrac{2,24}{22,4}=0,1mol\)
\(Fe+2HCl\rightarrow FeCl_2+H_2\)
0,1 0,1 ( mol )
( Cu không tác dụng với dd axit HCl )
\(m_{Fe}=0,1.56=5,6g\)
\(\rightarrow m_{Cu}=12-5,6=6,4g\)
\(\rightarrow\left\{{}\begin{matrix}\%m_{Fe}=\dfrac{5,6}{12}.100=46,66\%\\\%m_{Cu}=100\%-46,66\%=53,34\%\end{matrix}\right.\)
\(n_{H_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)
PTHH: Fe + 2HCl --> FeCl2 + H2
_____0,15<--------------------0,15
=> mFe = 0,15.56 = 8,4(g)
=> \(\left\{{}\begin{matrix}\%Fe=\dfrac{8,4}{24,4}.100\%=34,426\%\\\%Fe_2O_3=100\%-34,426\%=65,574\%\end{matrix}\right.\)
Đặt:
nCuO= x mol
nZnO= y mol
mhh= 80x + 81y= 12.1g (1)
CuO + 2HCl --> CuCl2 + H2O
x_____2x
ZnO + 2HCl --> ZnCl2 + H2
y______2y
nHCl= 2x + 2y= 0.3 mol (2)
Giải (1) và (2) :
x=0.05
y= 0.1
mCuO= 0.05*80=4g
mZnO= 0.1*81=8.1g
%CuO= 4/12.1*100%= 33.05%
%ZnO = 100-33.05=66.95%
a) nH2=0,05(mol)
Na + H2O -> NaOH + 1/2 H2
0,1_______________0,05(mol)
Na2O + H2O -> 2 NaOH
b) => mNa=0,1.23=2,3(g)
=>nNa2O= 14,7 - 2,3= 12,4(g)
