Bài 3 :

\(a) n_{CuO} = a(mol) ; n_{Fe_2O_3} = b(mol)\\ \Rightarrow 80a + 160b = 36(1)\\ CuO + H_2 \xrightarrow{t^o} Cu + H_2O\\ Fe_2O_3 + 3H_2 \xrightarrow{t^o} 2Fe + H_2O\\ n_{Cu} = n_{CuO} = a(mol)\\ n_{Fe} = 2n_{Fe_2O_3} = 2b(mol)\\ \Rightarrow 64a = 4.2b.56(2)\\ (1)(2) \Rightarrow a = 0,35 ; b = 0,05\\ m_{CuO} = 0,35.80 = 28(gam)\\ m_{Fe_2O_3} = 0,05.160 = 8(gam)\\ b) n_{H_2} = a + 3b = 0,5(mol) \Rightarrow V_{H_2} = 0,5.22,4 = 11,2(lít)\)

\(c) Fe + 2HCl \to FeCl_2 + H_2\\ n_{HCl} = 2n_{Fe} = 0,1.2 = 0,2(mol)\\ \Rightarrow m_{dd\ HCl} = \dfrac{0,2.36,5}{10,95\%} = 66,67(gam)\)

Bài 4 :

\(a) Zn + 2HCl \to ZnCl_2 + H_2\\ n_{H_2} = n_{Zn} = \dfrac{1,95}{65} = 0,03(mol)\\ V_{H_2} = 0,03.22,4= 0,672(lít)\\ b) n_{HCl} =2 n_{H_2} = 0,06(mol)\\ \Rightarrow C\%_{HCl} = \dfrac{0,06.36,5}{120}.100\% = 1,825\%\\ m_{dd\ sau\ pư} = 1,95 + 120 - 0,03.2 = 121,89(gam)\\ \Rightarrow C\%_{ZnCl_2} = \dfrac{0,03.136}{121,89}.100\% = 3,35\%\)

a)%mZnO=20% => %mCuO=100% - 20%=80%

b) mZnO=20%.25=5(g)=> nZnO=5/81(mol)

mCuO=25-5=20(g) => nCuO=20/80=0,25(mol)

PTHH: ZnO +2 HCl -> ZnCl2 + H2O

5/81_______10/81___5/81(mol)

CuO +2 HCl -> CuCl2 + H2O

0,25__0,5______0,25(mol)

 => nHCl=10/81 + 0,5=101/162(mol)

=>mHCl= 101/162 . 36,5=7373/324(g)

=> mddHCl= 7373/324 : 15%= 151,708(g)

 => VddHCl= 151,708/1,1=137,916(ml)

MgO + 2HCl -> MgCl2 + H2O

x            2x

Fe2O3 + 6HCl -> 2FeCl3 + 3H2O

 y             6y

CuO + 2HCl -> CuCl2 + H2O

z           2z

A--H2 dư----> MgO          + H2O

                         Fe

                         Cu

Fe2O3 + 3H2 -> 2Fe + 3H2O

ky

CuO + H2 -> Cu + H2O

kz

nH2O=1,62/18=0,09mol

Gọi nMgO=x, nFe2O3=y, nCuO=z (trong 4,8g hh A)

      nMgO=Kx, nFe2O3=Ky, nCuO=Kz (trong 0,09mol A)

=> kx+ky+kz =4,8

      3ky + kz= 0,09

=> 2ky = kx => 2y=x

                          40x + 160y +80z=4,8

                           nHCl=2x+6y+2z=5,84/36,5=0,16

=> x=0,02            => mMgO= 0,8g

      y=0,01                  mFe2O3=1,6g

      z=0,03                  mCuO=2,4g

*tk

PTHH: \(ZnO+2HCl\rightarrow ZnCl_2+H_2O\)

            \(CuO+2HCl\rightarrow CuCl_2+H_2O\)

Ta có: \(\%m_{ZnO}=20\%\) \(\Rightarrow\%m_{CuO}=80\%\)

Mặt khác: \(\left\{{}\begin{matrix}n_{Zn}=\dfrac{25\cdot20\%}{81}=\dfrac{5}{81}\left(mol\right)\\n_{CuO}=\dfrac{25\cdot80\%}{80}=0,25\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow n_{HCl}=\left(\dfrac{5}{81}+0,25\right)\cdot2=\dfrac{101}{162}\left(mol\right)\) 

\(\Rightarrow m_{ddHCl}=\dfrac{\dfrac{101}{162}\cdot36,5}{15\%}\approx151,71\left(g\right)\) \(\Rightarrow V_{ddHCl}=\dfrac{151,71}{1,1}\approx137,92\left(ml\right)\)             

a) Phương trình hóa học:

\(CuO+2HCl\rightarrow CuCl_2+H_2O\left(1\right)\)

\(Fe_2O_3+6HCl\rightarrow2FeCl_3+3H_2O\left(2\right)\)

\(n_{HCl}=0,2\times3=0,6\left(mol\right)\)

Gọi số mol Cuo và \(Fe_2O_3\) lần lượt là x và y (mol)

Theo bài ra ta có hệ phương trình:

\(\left\{{}\begin{matrix}80x+160y=20\\2x+6y=0,6\end{matrix}\right.\leftrightarrow\left\{{}\begin{matrix}x=0,15\\y=0,05\end{matrix}\right.\leftrightarrow\)

\(\Rightarrow m_{CuO}=0,15\times80=12\left(g\right)\)

\(\Rightarrow\%_{CuO}=\frac{12}{20}\times100\%=60\%\)

\(\Rightarrow\%_{Fe_2O_3}=100\%-60\%=40\%\)

b) Theo (1): \(n_{CuCl_2}=n_{CuO}=0,15\left(mol\right)\)

\(\Rightarrow m_{CuCl_2}=0,15\times135=20,25\left(g\right)\)

Theo (2): \(n_{FeCl_3}=2n_{Fe_2O_3}=0,1\left(mol\right)\)

\(\Rightarrow m_{FeCl_3}=0,1\times162,5=16,25\left(g\right)\)

\(n_{HCl}=0,4.2=0,8\left(mol\right)\\ Đặt:n_{CuO}=a\left(mol\right);n_{Fe_2O_3}=b\left(mol\right)\left(a,b>0\right)\\CuO+2HCl\rightarrow CuCl_2+H_2O\\ Fe_2O_3+6HCl\rightarrow2FeCl_3+3H_2O \\ \Rightarrow\left\{{}\begin{matrix}80a+160b=24\\2a+6b=0,8\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=0,1\\b=0,1\end{matrix}\right.\\ C1:m_{muối}=135a+2.162,5b=135.0,1+325.0,1=46\left(g\right)\\ C2:n_{H_2O}=\dfrac{n_{HCl}}{2}=0,4\left(mol\right)=n_{O\left(trongH_2O\right)}=n_{O\left(trong.oxit\right)}\\ \Rightarrow m_{muối}=m_{CuO,Fe_2O_3}-m_{O\left(trong.oxit\right)}+m_{Cl^-}=24-0,4.16+0,8.35,5=46\left(g\right)\\ b,m_{CuO}=80a=8\left(g\right);m_{Fe_2O_3}=160b=16\left(g\right)\)

Làm vài bài rồi ra sân bay check in đây

CuO+2HCl->CuCl₂+H₂O

x--------2x

Fe₂O₃+6HCl->2FeCl₃+3H₂O

y--------------6y

Ta  có :

\(\left\{{}\begin{matrix}56x+160y=24\\2x+6y=0,8\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}x=0,1\\y=0,1\end{matrix}\right.\)

=>m _CuO=0,1.56=5,6g

=>m _Fe2O3=0,1.160=16g

-> m _muối =0,1.135+0,2.162,5=46g

C2:n _H2O=0,4 mol

=>m _muối =24-0,4.16+0,8.35,5=46g