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a) Đặt: nMg=x(mol); nZnO=y(mol)
nH2SO4= 0,2(mol)
PTHH: Mg + H2SO4 -> MgSO4 + H2
x___________x____x_______x(mol)
ZnO + H2SO4 -> ZnSO4 + H2O
y____y______y(mol)
Ta có:
\(\left\{{}\begin{matrix}24x+81y=12,9\\22,4x=4,48\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0,2\\y=0,1\end{matrix}\right.\)
mMg=0,2.24=4,8(g)
%mMg=(4,8/12,9).100=37,209%
=>%mZnO=62,791%
b) nH2SO4=x+y=0,3(mol)
=> \(C\%ddH2SO4=\dfrac{0,3.98}{120}.100=24,5\%\)
PTHH: \(Fe+H_2SO_4\rightarrow FeSO_4+H_2\uparrow\)
a) Ta có: \(n_{H_2}=\dfrac{5,6}{22,4}=0,25\left(mol\right)=n_{Fe}\)
\(\Rightarrow m_{Fe}=0,25\cdot56=14\left(g\right)\) \(\Rightarrow m_{Cu}=6\left(g\right)\)
b) Theo PTHH: \(n_{FeSO_4}=0,25mol\) \(\Rightarrow m_{FeSO_4}=0,25\cdot152=38\left(g\right)\)
Mặt khác: \(\left\{{}\begin{matrix}m_{ddH_2SO_4}=\dfrac{0,25\cdot98}{10\%}=245\left(g\right)\\m_{H_2}=0,25\cdot2=0,5\left(g\right)\end{matrix}\right.\)
\(\Rightarrow m_{dd}=m_{hh}+m_{H_2SO_4}-m_{Cu}-m_{H_2}=258,5\left(g\right)\)
\(\Rightarrow C\%_{FeSO_4}=\dfrac{38}{258,5}\cdot100\%\approx14,7\%\)
pthh : Fe +H2SO4 → FeSO4 +H2
theo bài ra số mol của h2 =0,15 (mol)
theo pt : nFe=nH2=0,15 (mol)
mFe=0,15 .56 =8,4 (g) ⇒mCu=20-8,4=11,6 (g)
thôi thì mình làm cho bn vậy, câu a ko làm dc đâu, làm câu b thôi, làm sao biết dc chất nào dư khi chỉ có số mol 1 chất?
nK2SO3=0.1367(mol)
mddH2SO4=Vdd.D=200.1,04=208(g)
K2SO3+H2SO4-->K2SO4+H2O+SO2
0.1367----0.1367----0.1367---------0.1367 (mol)
mddspu=100+208-0,1367.64=299.2512(g) ; mK2SO4=0,1367.174=23.7858(g)
==>C%=23.7858.100/299.512=7.94%
2)pt bn tự ghi nhé
ta có hệ pt: 56a+27b=11 và a+3b/2=8.96/22.4==>a=0.1, b=0.2
==>%Fe=0.1x56x100/11=50.9%
%Al=100%-50.9%=49.1%
b)nH2SO4= 0.7(mol)==>VddH2SO4=0.7/2=0.35(L)
\(n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)
PTHH:
\(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)
0,2 0,2 0,2 0,2
\(a,\%m_{Fe}=\dfrac{0,2.56}{20}.100\%=56\%\)
\(\%m_{Cu}=100\%-56\%=44\%\)
\(b,C_{M\left(H_2SO_4\right)}=\dfrac{0,2}{0,1}=2\left(M\right)\)
\(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)
\(1\) \(1\) \(1\)
\(0,2\) \(0,2\) \(0,2\)
\(n_{H_2}=\dfrac{V}{22,4}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)
\(m_{Fe}=n.M=0,2.56=11,2\left(g\right)\)
\(^0/_0Fe=\dfrac{11,2}{20}.100^0/_0=56^0/_0\)
\(^0/_0Cu=100^0/_0-56^0/_0=44^0/_0\)
\(C_{M_{H_2SO_4}}=\dfrac{n}{V_{dd}}=\dfrac{0,2}{0,1}=2M\)
a.Mg + H2SO4 -> MgSO4 + H2
b.\(nH2=\dfrac{4.704}{22.4}=0.21mol\) = nMg
mMg = 0.21\(\times24=5.04g\)
\(\%mMg=\dfrac{5.04\times100}{25}=20.16\%\)
\(\%mAg=100-20.16=79.84\%\)
c.MgSO4 + 2KOH -> K2SO4 + Mg(OH)2
0.21 0.42
H2SO4 + 2KOH -> K2SO4 + H2O
0.04 0.08
\(nH2SO4=\dfrac{9.8\times250}{100\times98}=0.25mol\)
Mà nH2SO4 phản ứng = nH2 = 0.21 mol
\(\Rightarrow nH2SO4dư=0.25-0.21=0.04mol\)
=> nKOH = 0.42 + 0.08 = 0.5mol
\(\Rightarrow CM_{KOH}=\dfrac{0.5}{0.625}=0.8M\)
a, \(n_{CO_2}=\dfrac{2,479}{24,79}=0,1\left(mol\right)\)
PT: \(MgO+2CH_3COOH\rightarrow\left(CH_3COO\right)_2Mg+H_2O\)
\(MgCO_3+2CH_3COOH\rightarrow\left(CH_3COO\right)_2Mg+CO_2+H_2O\)
Theo PT: \(n_{MgCO_3}=n_{CO_2}=0,1\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}\%m_{MgCO_3}=\dfrac{0,1.84}{10,4}.100\%\approx80,77\%\\\%m_{MgO}\approx19,23\%\end{matrix}\right.\)
b, \(n_{MgO}=\dfrac{10,4-0,1.84}{40}=0,05\left(mol\right)\)
Theo PT: \(n_{CH_3COOH}=2n_{MgO}+2n_{MgCO_3}=0,3\left(mol\right)\)
\(\Rightarrow C_{M_{CH_3COOH}}=\dfrac{0,3}{0,2}=1,5\left(M\right)\)
\(a)2Al+6HCl\rightarrow2AlCl_3+3H_2\\ Fe+2HCl\rightarrow FeCl_2+H_2\\ b)n_{H_2}=\dfrac{5,6}{22,4}=0,25mol\\ n_{Al}=a;n_{Fe}=b\\ \left\{{}\begin{matrix}3a+b=0,25\\27a+56b=8,3\end{matrix}\right.\\ a=\dfrac{19}{470};b=\dfrac{121}{940}\\ \%m_{Al}=\dfrac{\dfrac{19}{470}\cdot27}{8,3}\cdot100=13,15\%\\ \%m_{Fe}=100-13,15=86,85\%\\ c)n_{HCl}=3\cdot\dfrac{19}{470}+2\cdot\dfrac{121}{940}=\dfrac{89}{235}mol\\ m_{ddHCl=}=\dfrac{\dfrac{89}{235}\cdot36,5}{7,3}\cdot100=189g\\ d)n_{AlCl_3}=n_{Al}=\dfrac{19}{470}mol\\ n_{Fe}=n_{FeCl_2}=\dfrac{121}{940}mol\)
\(m_{dd}=8,3+189-0,25.2=196,8g\\ C_{\%AlCl_3}=\dfrac{\dfrac{19}{470}\cdot133,8}{196,8}\cdot100=2,8\%\\ C_{\%FeCl_2}=\dfrac{\dfrac{121}{940}127}{196,8}\cdot100=8,3\%\)
Vì Cu không tác dụng với HCl
\(n_{H2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)
Pt : \(Fe+2HCl\rightarrow FeCl_2+H_2|\)
1 2 1 1
0,1 0,2 0,1
a) \(n_{Fe}=\dfrac{0,1.1}{1}=0,1\left(mol\right)\)
\(m_{Fe}=0,1.56=5,6\left(g\right)\)
\(m_{Cu}=12-5,6=6,4\left(g\right)\)
b) \(n_{HCl}=\dfrac{0,1.2}{1}=0,2\left(mol\right)\)
200ml = 0,2l
\(C_{M_{ddHCl}}=\dfrac{0,2}{0,2}=1\left(M\right)\)
c) 0/0Fe = \(\dfrac{5,6.100}{12}=46,67\)0/0
0/0Cu = \(\dfrac{6,4.100}{12}=53,33\)0/0
Chúc bạn học tốt
Bài 1 :
\(n_{H_2}=\dfrac{2.24}{22.4}=0.1\left(mol\right)\)
\(Fe+2HCl\rightarrow FeCl_2+H_2\)
\(0.1..................................0.1\)
\(m_{hh}=x=0.1\cdot56+4.4=10\left(g\right)\)
Bài 2 :
\(n_{H_2}=\dfrac{2.24}{22.4}=0.1\left(mol\right)\)
\(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)
\(0.1.......0.1..........0.1.............0.1\)
\(m_{Fe_2O_3}=7.2-0.1\cdot56=1.6\)
\(n_{Fe_2O_3}=\dfrac{7.2-0.1\cdot56}{160}=0.01\left(mol\right)\)
\(Fe_2O_3+3H_2SO_4\rightarrow Fe_2\left(SO_4\right)_3+3H_2O\)
\(0.01...........0.03..............0.01\)
\(c.\)
\(V_{dd_{H_2SO_4}}=\dfrac{0.1+0.03}{1}=0.13\left(l\right)\)
\(d.\)
\(C_{M_{FeSO_4}}=\dfrac{0.1}{0.13}=\dfrac{10}{13}\left(M\right)\)
\(C_{M_{Fe_2\left(SO_4\right)_3}}=\dfrac{0.03}{0.13}=\dfrac{3}{13}\left(M\right)\)
a, \(n_{H_2SO_4}=0,45.0,2=0,09\left(mol\right)\)
PTHH: FeO + H2SO4 → FeSO4 + H2O
Mol: a a
PTHH: MgO + H2SO4 → MgSO4 + H2O
Mol: b b
Ta có: \(\left\{{}\begin{matrix}72a+40b=4,48\\a+b=0,09\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=0,0275\\b=0,0625\end{matrix}\right.\)
\(\%m_{FeO}=\dfrac{0,0275.72.100\%}{4,48}=44,196\%\)
\(\%m_{MgO}=100-44,196=55,804\%\)
b,
PTHH: FeO + H2SO4 → FeSO4 + H2O
Mol: 0,0275 0,0275
PTHH: MgO + H2SO4 → MgSO4 + H2O
Mol: 0,0625 0,0625
\(C_{M_{ddFeSO_4}}=\dfrac{0,0275}{0,2}=0,1375M\)
\(C_{M_{ddMgSO_4}}=\dfrac{0,0625}{0,2}=0,3125M\)