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nH2=0.56:22,4=0,025 mol
Fe+H2SO4----->FeSO4+H2
2AL+3H2SO4----->AL2(SO4)3 +3H2
Gọi x,y làn lượt là số mol Fe và AL
ta có hệ pt
mFe=0,01.56=0,56 g
mAl=0,83-0,56=0,27 g
%mFe=(0,56:0,83).100=67,47%
%mAl=100-67,47=32,53%
nCaCO3 = 0,1 mol
nH2 = 0,125 mol
Pt: Mg + 2HCl --> MgCl2 + H2
.....0,125 mol<----------------0,125 mol
.....MgCO3 + 2HCl --> MgCl2 + H2O + CO2
.....0,1 mol<----------------------------------0,1 mol
......CO2 + Ca(OH)2 --> CaCO3 + H2O
....0,1 mol<---------------0,1 mol
mA = 0,125 . 24 + 0,1 . 84 = 11,4 (g)
% mMg = \(\dfrac{0,125\times4}{11,4}.100\%=26,3\%\)
% mMgCO3 = \(\dfrac{0,1\times84}{11,4}.100\%=73,7\%\)
nH2 \(\approx\)0,2 (mol)
Mg + 2HCl \(\rightarrow\) MgCl2 + H2 (1)
0,2 <------------ 0,2 <----- 0,2 (mol)
MgO + 2HCl \(\rightarrow\) MgCl2 + H2O (2)
b) %mMg = \(\frac{0,2.24}{8,8}\) . 100% =54,55%
%mMgO = 45,45%
c) mMgO = 8,8 - 0,2 . 24 = 4(g)
=> nMgO=0,1 (mol)
Theo pt(2) nMgCl2 = nMg = 0,1 (mol)
=> \(\Sigma n_{MgCl_2}\) = 0,2 + 0,1 = 0,3 (mol)
mmuối = 0,3 . 95 = 28,5 (g)
a, \(Fe+2HCl\rightarrow FeCl_2+H_2\)
b, \(n_{H_2}=\dfrac{8,96}{22,4}=0,4\left(mol\right)\)
Theo PT: \(n_{Fe}=n_{H_2}=0,4\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}\%m_{Fe}=\dfrac{0,4.56}{35}.100\%=64\%\\\%m_{Cu}=36\%\end{matrix}\right.\)
Đặt : \(n_{Al}=a\left(mol\right),n_{Fe}=b\left(mol\right)\)
\(m_{hh}=27a+56b=6.95\left(g\right)\left(1\right)\)
\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
\(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)
\(n_{H_2}=1.5a+b=\dfrac{3.92}{22.4}=0.175\left(mol\right)\left(2\right)\)
\(\left(1\right),\left(2\right):a=0.05,b=0.1\)
\(\%Al=\dfrac{0.05\cdot27}{6.95}\cdot100\%=19.42\%\)
\(\%Fe=100-19.42=80.58\%\)
\(n_{H_2}=\dfrac{3,92}{22,4}=0,175(mol)\\ a,PTHH:2Al+3H_2SO_4\to Al_2(SO_4)_3+3H_2\\ Fe+H_2SO_4\to FeSO_4+H_2\\b,n_{Al}=x(mol);n_{Fe}=y(mol)\\ \Rightarrow 27x+56y=6,95;1,5x+y=0,175\\ \Rightarrow x=0,05(mol);y=0,1(mol)\\ \Rightarrow \%_{Al}=\dfrac{0,05.27}{6,95}.100\%=19,42\%\\ \Rightarrow \%_{Fe}=100\%-19,42\%=80,58\% \)
Gọi nK2O=a, nMgO=b trong 8g hh
K2O + H2SO4 \(\rightarrow\) K2SO4 + H2O
a \(\rightarrow\) a (mol)
MgO + H2SO4 \(\rightarrow\) MgSO4 + H2O
b \(\rightarrow\) b (mol)
K2SO4 + 2NaOH \(\rightarrow\) Na2SO4 + 2KOH
MgSO4 + 2NaOH \(\rightarrow\) Na2SO4 + Mg(OH)2
b \(\rightarrow\) b (mol)
nMg(OH)2 = \(\frac{2,9}{58}\) = 0,05 (mol)
\(\Rightarrow\) b = 0,05 (mol)
\(\Rightarrow\) %mMgO = \(\frac{0,05.40}{8}\) . 100% = 25%
%mK2O = 75%
cám ơn bạn