Bài 1:

a+b) PTHH: \(Fe+H_2SO_4\rightarrow FeSO_4+H_2\uparrow\)

Ta có: \(n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)=n_{Fe}\)

\(\Rightarrow m_{Fe}=0,2\cdot56=11,2\left(g\right)\) \(\Rightarrow m_{Cu}=6,4\left(g\right)\)

\(\Rightarrow\left\{{}\begin{matrix}\%m_{Fe}=\dfrac{11,2}{17,6}\cdot100\%\approx63,64\%\\\%m_{Cu}=36,36\%\end{matrix}\right.\)

c) Ta có: \(n_{Cu}=\dfrac{6,4}{64}=0,1\left(mol\right)\)

Bảo toàn nguyên tố: \(n_{Fe_2\left(SO_4\right)_3}=\dfrac{1}{2}n_{Fe}=0,1\left(mol\right)=n_{CuSO_4}\)

\(\Rightarrow m_{muối}=0,1\cdot400+0,1\cdot160=56\left(g\right)\)

Bài 2:

Quy đổi hh gồm Fe (a mol) và O (b mol)

\(\Rightarrow56a+16b=27,6\)  (1)

Ta có: \(n_{SO_2}=\dfrac{5,04}{22,4}=0,225\left(mol\right)\)

Bảo toàn electron: \(3n_{Fe}=2n_O+2n_{SO_2}\) \(\Rightarrow3a-2b=0,45\)  (2)

Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}a=0,39\\b=0,36\end{matrix}\right.\)

Bảo toàn nguyên tố: \(n_{Fe_2\left(SO_4\right)_3}=\dfrac{1}{2}n_{Fe}=0,195\left(mol\right)\) \(\Rightarrow m_{Fe_2\left(SO_4\right)_3}=0,195\cdot400=78\left(g\right)\)

a)

$Fe + 2HCl \to FeCl_2 + H_2$
$FeO + 2HCl \to FeCl_2 + H_2O$

b)

Theo PTHH : $n_{Fe} = n_{H_2} = \dfrac{3,36}{22,4} = 0,15(mol)$
$m_{Fe} = 0,15.56 = 8,4(gam)$
$m_{FeO} = 12 - 8,4 = 3,6(gam)$

$n_{FeO} =0,05(mol)$
Theo PTHH : $n_{HCl} = 2n_{Fe} + 2n_{FeO} = 0,4(mol)$

$V_{dd\ HCl} = \dfrac{0,4}{2} = 0,2(lít)$

c) $Fe + CuSO_4 \to FeSO_4 + Cu$

$n_{Cu} = n_{Fe} = 0,15(mol) \Rightarrow m_{chất\ rắn} = m_{FeO} + m_{Cu}$

$= 3,6 + 0,15.64 = 13,2(gam)$

\(n_{Al}=a\left(mol\right)\)

\(n_{Fe}=b\left(mol\right)\)

\(m=27a+56b=19.3\left(g\right)\left(1\right)\)

\(n_{H^+}=0.2\cdot2+0.2\cdot2.25\cdot2=1.3\left(mol\right)\)

\(2Al+6H^+\rightarrow2Al^{3+}+3H_2\)

\(Fe+2H^+\rightarrow Fe^{2+}+H_2\)

\(n_{H^+}=3a+2b=1.3\left(mol\right)\left(2\right)\)

\(\left(1\right),\left(2\right):a=0.3,b=0.2\)

\(\%Al=\dfrac{0.3\cdot27}{19.3}\cdot100\%=41.96\%\)

\(\%Fe=58.04\%\)

\(b.\)

\(n_{H_2}=\dfrac{1}{2}n_{H^+}=0.65\left(mol\right)\)

Bảo toàn khối lượng : 

\(m_{Muối}=19.3+0.4\cdot36.5+0.45\cdot98-0.65\cdot2=76.7\left(g\right)\)

em cảm ơn ạ!

a. PTHH:

Cu + H₂SO₄ ---x--->

Mg + H₂SO₄ ---> MgSO₄ + H₂

b. Ta có: \(n_{H_2SO_4}=2.\dfrac{100}{1000}=0,2\left(mol\right)\)

Theo PT: \(n_{Mg}=n_{H_2SO_4}=0,2\left(mol\right)\)

\(\Rightarrow m_{Mg}=0,2.24=4,8\left(g\right)\)

\(\Rightarrow\%_{m_{Mg}}=\dfrac{4,8}{6}.100\%=80\%\)

\(\%_{m_{Cu}}=100\%-80\%=20\%\)

c. Theo PT: \(n_{H_2}=n_{Mg}=0,2\left(mol\right)\)

\(\Rightarrow V_{H_2}=0,2.22,4=4,48\left(lít\right)\)

d. PTHH: \(Cu+2H_2SO_{4_đ}\overset{t^o}{--->}CuSO_4+SO_2+2H_2O\)

a) Fe + 2HCl --> FeCl₂ + H₂

b) \(n_{H_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)

PTHH: Fe + 2HCl --> FeCl₂ + H₂

_____0,15<-0,3<----0,15<---0,15

\(\left\{{}\begin{matrix}\%Fe=\dfrac{0,15.56}{12}.100\%=70\%\%\\\%Cu=100\%-70\%=30\%\end{matrix}\right.\)

c) m_HCl = 0,3.36,5 = 10,95 (g)

=> \(m_{dd}=\dfrac{10,95.100}{10}=109,5\left(g\right)\)

d) mdd  = 12 + 109,5 - 0,15.2 = 121,2 (g)

 \(C\%\left(FeCl_2\right)=\dfrac{0,15.127}{121,2}.100\%=15,718\%\)

a: \(Cu+2HCl->CuCl_2+H_2\)

\(Fe+2HCl->FeCl_2+H_2\)

giup em

Bài 3 : 

a) $Mg + H_2SO_4 \to MgSO_4 + H_2$
$n_{Mg} = n_{H_2} = \dfrac{3,36}{22,4} = 0,15(mol)$
$\%m_{Mg} = \dfrac{0,15.24}{13,2}.100\% = 27,27\%$
$\%m_{Cu} = 100\% -27,27\% = 72,73\%$

b) $n_{Cu} = \dfrac{13,2 - 0,15.24}{64}= 0,15(mol)$

$\Rightarrow m_{muối} = 0,15.120 + 0,15.160= 42(gam)$

Bài 4 : 

Gọi $n_{Fe} = a(mol) ; n_{Mg} = b(mol)$
$56a + 24b = 18,4(1)$

$Fe + 2HCl \to FeCl_2 + H_2$
$Mg + 2HCl \to MgCl_2 + H_2$

Theo PTHH : $n_{H_2} = a + b = \dfrac{11,2}{22,4} = 0,5(2)$

Từ (1)(2) suy ra a = 0,2 ; b = 0,3

$\%m_{Fe} = \dfrac{0,2.56}{18,4}.100\%  = 60,87\%$

$\%m_{Mg} = 100\% -60,87\% = 39,13\%$

b) $n_{HCl} = 2n_{H_2} = 1(mol)$
$V_{dd\ HCl} = \dfrac{1}{0,8}=  1,25(lít)$

3a) \(Mg+H_2SO_4\rightarrow MgSO_4+H_2\)

\(n_{H_2}=n_{Mg}=0,15\left(mol\right)\)

=> \(\%m_{Mg}=\dfrac{0,15.24}{13,2}.100=27,28\%\)

\(\%m_{Cu}=100-27,28=72,73\%\)

b) \(n_{Cu}=\dfrac{13,2-3,6}{64}=0,15\left(mol\right)\)

Cu + 2H2SO4 → CuSO4 + SO2 + 2H2O

0,15------------------->0,15

Mg + 2H2SO4 → MgSO4 + SO2 + 2H2O

0,15------------------->0,15

\(m_{muối}=0,15.160+0,15.120=42\left(g\right)\)

a.\(n_{H_2}=\dfrac{V_{H_2}}{22,4}=\dfrac{8,96}{22,4}=0,4mol\)

Gọi \(\left\{{}\begin{matrix}n_{Fe}=x\\n_{Zn}=y\end{matrix}\right.\)

\(Fe+2HCl\rightarrow FeCl_2+H_2\)

 x                                      x ( mol )

\(Zn+2HCl\rightarrow ZnCl_2+H_2\)

 y                                        y   ( mol )

Ta có:

\(\left\{{}\begin{matrix}56x+65y=25,55\\x+y=0,4\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x=0,05\\y=0,35\end{matrix}\right.\)

\(\Rightarrow m_{Fe}=0,05.56=2,8g\)

\(\Rightarrow m_{Zn}=0,35.65=22,75g\)

\(\%m_{Fe}=\dfrac{2,8}{25,55}.100=10,95\%\)

\(\%m_{Zn}=100\%-10,95\%=89,05\%\)

b.\(n_{HCl}=2.0,05+2.0,35=0,8mol\)

\(C_M=\dfrac{n}{V}\Rightarrow V=\dfrac{n}{C_M}=\dfrac{0,8}{2}=0,4l\)

Đặt \(\left\{{}\begin{matrix}n_{Al}=x\\n_{Fe}=y\end{matrix}\right.\) ( mol ) \(\rightarrow m_{hh}=27x+56y=5,54\left(g\right)\)  (1)

\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)

 x                                                   1,5x    ( mol )

\(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)

 y                                           y       ( mol )

\(n_{H_2}=1,5x+y=\dfrac{3,584}{22,4}=0,16\left(mol\right)\)   (1)

\(\left(1\right);\left(2\right)\Rightarrow\left\{{}\begin{matrix}x=0,06\\y=0,07\end{matrix}\right.\)

\(\left\{{}\begin{matrix}\%m_{Al}=\dfrac{0,06.27}{5,54}.100=29,24\%\\\%m_{Fe}=100-29,24=70,76\%\end{matrix}\right.\)