nH2=0.1(mol)

PTHH:Fe+H2SO4->FeSO4+H2

Fe2O3+3H2SO4->Fe2(SO4)3+3H2O

Theo pthh1:nFe=nH2->nFe=0.1(mol)

mFe=0.1*56=5.6(g)->%Fe=5.6:21.6*100=25.9%

%Fe2O3=100-25.9=74.1%

câu b câu c không liên quan đến đề bài bạn ơi,Chỉ có FeSO4,Fe2(SO4)3,và HCl thôi nhé,không có H2SO4 và MgSO4 đâu

\(n_{H_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)

PTHH: \(Fe_2O_3+3H_2\xrightarrow[]{t^o}2Fe+3H_2O\)

            0,1<-----0,3------>0,2

=> \(\left\{{}\begin{matrix}m_{Fe_2O_3}=0,1.160=16\left(g\right)\\m_{Fe}=21,6-16=5,6\left(g\right)\end{matrix}\right.\)

b) \(\left\{{}\begin{matrix}\%m_{Fe_2O_3}=\dfrac{16}{21,6}.100\%=74,07\%\\\%m_{Fe}=100\%=74,07\%=25,93\%\end{matrix}\right.\)

c) \(m_{Fe\left(sau\right)}=0,2.56+5,6=16,8\left(g\right)\)

\(n_{H_2} = \dfrac{2,24}{22,4} = 0,1(mol)\)

\(n_{H^+} = n_{HCl} = 0,8(mol)\)

Coi X gồm Fe,O

2H⁺   +     2e  → H₂

0,2...........0,2......0,1..................(mol)

2H⁺   +     O^2-    →   H₂O

0,6..........0,3.............................(mol)

Bảo toàn electron : 

\(2n_{Fe} = 2n_{H_2} + 2n_O\\ \Rightarrow n_{Fe\ pư} = \dfrac{0,3.2+0,1.2}{2} = 0,4(mol)\)

Suy ra : 

m_X = m_{Fe phản ứng} + m_O + m_{Fe dư} = 0,4.56 + 0,3.16 + 2,8 = 30 gam

a, \(n_{H_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)

m_{hh Zn và Fe} = 21,6-3 = 18,6 (g)

PTHH: Zn + H₂SO₄ → ZnSO₄ + H₂

Mol:      x                                           x

PTHH: Fe + H₂SO₄ → FeSO₄ + H₂

Mol:      y                                           y 

Ta có: \(\left\{{}\begin{matrix}65x+56y=18,6\\x+y=0,3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0,2\\y=0,1\end{matrix}\right.\)

\(\%m_{Zn}=\dfrac{0,2.65.100\%}{21,6}=60,19\%\)

\(\%m_{Fe}=\dfrac{0,1.56.100\%}{21,6}=25,93\%\)

\(\%m_{Cu}=100-60,19-25,93=13,88\%\)

b,

PTHH: Zn + H₂SO₄ → ZnSO₄ + H₂

Mol:     0,2     0,2                            0,2

PTHH: Fe + H₂SO₄ → FeSO₄ + H₂

Mol:     0,1      0,1                            0,1 

\(m_{H_2SO_4}=\left(0,1+0,2\right).98=29,4\left(g\right)\Rightarrow m_{ddH_2SO_4}=\dfrac{29,4.100\%}{25\%}=117,6\left(g\right)\)

c,m_{dd sau pư} = 21,6+117,6- (0,1+0,2).2 = 138,6 (g)

\(C\%_{ddZnSO_4}=\dfrac{0,2.161.100\%}{138,6}=23,23\%\)

\(C\%_{ddFeSO_4}=\dfrac{0,1.152.100\%}{138,6}=10,97\%\)

\(n_{HCl}=\dfrac{14,6}{36,5}=0,4\left(mol\right)\\ Fe+2HCl\rightarrow FeCl_2+H_2\\ n_{Fe}=n_{H_2}=n_{FeCl_2}=\dfrac{n_{HCl}}{2}=0,2\left(mol\right)\\ a,m_{Fe}=0,2.56=11,2\left(g\right)\\ b,m_{FeCl_2}=0,2.127=25,4\left(g\right)\\ V_{H_2\left(đktc\right)}=0,2.22,4=4,48\left(l\right)\)

Gọi nFe = a (mol); nMg = b (mol)

56a + 24b = 8 (1)

nH2 = 4,48/22,4 = 0,2 (mol)

PTHH: 

Fe + 2HCl -> FeCl2 + H2

a ---> a ---> a ---> a

Mg + 2HCl -> MgCl2 + H2

b ---> b ---> b ---> b

a + b = 0,2 (2)

(1)(2) => a = b = 0,1 (mol)

mFe = 0,1 . 56 = 5,6 (g)

%mFe = 5,6/8 = 70%

%mMg = 100% - 70% = 30%

nHCl = 0,1 . 2 + 0,1 . 2 = 0,4 (mol)

CMddHCl = 0,4/0,1 = 4M

a) PTHH: \(MgCO_3\xrightarrow[]{t^o}MgO+CO_2\uparrow\)

                           a______a_______a           (mol)

                \(BaCO_3\xrightarrow[]{t^o}BaO+CO_2\uparrow\)

                         b_______b______b              (mol)

Ta lập HPT: \(\left\{{}\begin{matrix}84a+197b=40,7\\40a+153b=25,3\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}a=0,25\\b=0,1\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}\%m_{MgCO_3}=\dfrac{0,25\cdot84}{40,7}\cdot100\%\approx51,6\%\\\%m_{BaCO_3}=48,4\%\\V_{CO_2}=\left(0,25+0,1\right)\cdot22,4=7,84\left(l\right)\end{matrix}\right.\)

b) PTHH: \(MgO+2HCl\rightarrow MgCl_2+H_2O\)

                \(BaO+2HCl\rightarrow BaCl_2+H_2O\)

Theo PTHH: \(n_{HCl}=2n_{MgO}+2n_{BaO}=0,7\left(mol\right)\) \(\Rightarrow V_{ddHCl}=\dfrac{0,7}{2,5}=0,28\left(l\right)=280\left(ml\right)\)

*Phần c và d tương tự câu b

Đặt \(\left\{{}\begin{matrix}n_{Fe_2O_3}=x\left(mol\right)\\n_{PbO}=y\left(mol\right)\end{matrix}\right.\)

\(PTHH:Fe_2O_3+3H_2\underrightarrow{t^o}2Fe+3H_2O\\ \left(mol\right)......x\rightarrow...3x......2x.....3x\\ PTHH:PbO+H_2\underrightarrow{t^o}Pb+H_2O\\ \left(mol\right)......y\rightarrow.y.....y......y\\ m_{Fe_2O_3}+m_{PbO}=\Sigma m_{hh}\\ \Leftrightarrow160x+223y=76,6\left(1\right)\\ m_{Fe}+m_{Pb}=\Sigma m_{kl}\\ \Leftrightarrow56.2x+207y=63,8\\ \Leftrightarrow112x+207y=63,8\left(2\right)\\ \xrightarrow[\left(1\right)]{\left(2\right)}\left\{{}\begin{matrix}160x+223y=76,6\\112x+207y=63,8\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0,2\\y=0,2\end{matrix}\right.\)

\(\left\{{}\begin{matrix}\%m_{Fe_2O_3}=\dfrac{0,2.160}{76,6}.100\%=41,8\%\\\%m_{PbO}=100\%-41,8\%=58,2\%\end{matrix}\right.\)

\(\Sigma n_{H_2}=3x+y=3.0,2+0,2=0,8\left(mol\right)\\ \Sigma V_{H_2}=0,8.22,4=17,92\left(l\right)\)

Câu c là H2 chứ bạn