\(n_{Cu} = a ; n_{Al} = b ; n_{Fe} = c(mol)\\ \Rightarrow 64a + 27b + 56c = 28,6(1)\\ 2Al + 6HCl \to 2AlCl_3 + 3H_2\\ Fe + 2HCl \to FeCl_2 + H_2\\ n_{H_2} = 1,5b + c = \dfrac{13,44}{22,4} = 0,6(2)\\ \text{Mặt khác} : n_{O_2} = \dfrac{8,96}{22,4} = 0,4(mol)\\ 2Cu + O_2 \xrightarrow{t^o} 2CuO\\ 4Al + 3O_2 \xrightarrow{t^o} 2Al_2O_3\\ 4Fe + 3O_2 \xrightarrow{t^o} 2Fe_2O_3\\ \)

Ta có :

\(\dfrac{n_X}{n_{O_2}}=\dfrac{a+b+c}{0,5a +0,75b + 0,75c} = \dfrac{0,6}{0,4}(3)\\ (1)(2)(3)\Rightarrow a = \dfrac{317}{1460} ; b = \dfrac{121}{365}; c = \dfrac{15}{146}\\ \%m_{Cu} = \dfrac{\dfrac{317}{1460}.64}{28,6}.100\% = 48,59\%\\ \%m_{Al} = \dfrac{\dfrac{121}{365}.27}{28,6}.100\% = 31,3\%\\ \%m_{Fe} = 100\% - 41,59\% - 31,3\% = 27,11\%\)

\(n_{Al}=\dfrac{5,4}{27}=0,2\left(mol\right)\\ 2Al+3Cl_2\underrightarrow{^{to}}2AlCl_3\\ n_{Cl_2}=\dfrac{3}{2}.0,2=0,3\left(mol\right)\\ \Rightarrow V=V_{Cl_2\left(đktc\right)}=0,3.22,4=6,72\left(l\right)\\ n_{AlCl_3}=n_{Al}=0,2\left(mol\right)\\ \Rightarrow m_{AlCl_3}=0,2.133,5=26,7\left(g\right)\)

Gọi số mol Al, Mg là a, b (mol)

\(n_{H_2}=\dfrac{13,44}{22,4}=0,6\left(mol\right)\)

PTHH: 2Al + 6HCl --> 2AlCl₃ + 3H₂

            a--------------->a------>1,5a

            Mg + 2HCl --> MgCl₂ + H₂

             b--------------->b---->b

=> \(\left\{{}\begin{matrix}1,5a+b=0,6\\133,5a+95b=55,2\end{matrix}\right.\)

=> a = 0,2 (mol); b = 0,3 (mol)

\(\left\{{}\begin{matrix}\%m_{Al}=\dfrac{0,2.27}{0,2.27+0,3.24}.100\%=42,857\%\\\%m_{Mg}=\dfrac{0,3.24}{0,2.27+0,3.24}.100\%=57,143\%\end{matrix}\right.\)

\(\left\{{}\begin{matrix}Al\\Mg\end{matrix}\right.+HCl->\left\{{}\begin{matrix}AlCl3\\MgCl2\end{matrix}\right.+H2\)

2Al + 3HCl -> 2AlCl3 + 3H2

0,2      0,3                      0,3

Mg + 2HCl -> MgCl2 + H2

0,3      0,6                     0,3

=> mHCl dùng = 0,9 . 36,5 = 32,85 (g)

=> mH2 = 0,6 . 2 = 1,2 (g)

Bảo toàn khối lượng :

=> mX = 55,2 + 1,2 - 32,85 = 23,55 (g)

Ta có :

\(\left\{{}\begin{matrix}3x+2y=1,2\left(bt-e\right)\\133,5x+95y=55,2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0,2\left(mol\right)\\y=0,3\left(mol\right)\end{matrix}\right.\)

\(\left\{{}\begin{matrix}\%mAl=\dfrac{0,2.27}{0,2.27+0,3.24}=42,85\%\\\%mMg=100\%-42,85\%=57,15\%\end{matrix}\right.\)

a. \(n_{Al_2O_3}=\dfrac{10,2}{102}=0,1\left(mol\right)\)

PTHH : Al₂O₃ + 6HCl -> 2AlCl₃ + 3H₂O

              0,1         0,6          0,2                      ( mol )

\(m_{HCl}=0,6.36,5=21,9\left(g\right)\)

\(m_{AlCl_3}=0,2.133,5=26,7\left(g\right)\)

b. 

PTHH : 3O₂ + 4Al -> 2Al₂O₃

              0,15                 0,1         ( mol) 

\(V_{O_2}=0,15.22,4=3,36\left(l\right)\)

a. \(n_{Al_2O_3}=\dfrac{10,2}{102}=0,1\left(mol\right)\)

PTHH : Al₂O₃ + 3HCl -> 2AlCl₃ + 3H₂O

              0,1         0,3          0,2                      ( mol )

\(m_{HCl}=0,3.36,5=10,95\left(g\right)\)

\(m_{AlCl_3}=0,2.133,5=26,7\left(g\right)\)

b. 

PTHH : 3O₂ + 4Al -> 2Al₂O₃

              0,15                 0,1         ( mol) 

\(V_{O_2}=0,15.22,4=3,36\left(l\right)\)

\(m_{HCl}=\dfrac{219.10}{100}=21,9\left(g\right)\)

\(n_{HCl}=\dfrac{21,9}{36,5}=0,6\left(mol\right)\)

PTHH :

\(2Al+6HCl\rightarrow2AlCl_3+3H_2\uparrow\)

0,2      0,6                         0,3 

\(b,m_{Al}=0,2.27=5,4\left(g\right)\)

\(c,V_{H_2}=n.22,4=0,3.22,4=6,72\left(l\right)\)

\(a.2Al+6HCl\xrightarrow[]{}2AlCl_3+3H_2\\ b.m_{HCl}=\dfrac{219.10\%}{100\%}=21,9\left(g\right)\\ n_{HCl}=\dfrac{21,9}{36,5}=0,6\left(mol\right)\\ 2Al+6HCl\xrightarrow[]{}2AlCl_3+3H_2\\ n_{Al}=\dfrac{0,6.2}{6}=0,2\left(mol\right)\\ m_{Al}=0,2.27=5,4\left(g\right)\\ n_{H_2}=\dfrac{0,6.3}{6}=0,3\left(mol\right)\\ V_{H_2}=0,3.22,4=6,72\left(l\right)\)

a) PTHH: 2Al + 3H₂SO₄ --> Al₂(SO₄)₃ + 3H₂

b) \(n_{H_2}=\dfrac{0,672}{22,4}=0,03\left(mol\right)\)

PTHH: 2Al + 3H₂SO₄ --> Al₂(SO₄)₃ + 3H₂

_____0,02<---0,03<---------------------0,03

=> \(\left\{{}\begin{matrix}\%Al=\dfrac{0,02.27}{2,16}.100\%=25\%\\\%Cu=100\%-25\%=75\%\end{matrix}\right.\)

c) m_H2SO4 = 0,03.98 = 2,94 (g)

=> \(C\%\left(H_2SO_4\right)=\dfrac{2,94}{200}.100\%=1,47\%\)

a, \(2H_2+O_2\underrightarrow{t^o}2H_2O\)

b, \(n_{H_2}=\dfrac{2,8}{22,4}=0,125\left(mol\right)\)

Theo PT: \(n_{O_2}=\dfrac{1}{2}n_{H_2}=0,0625\left(mol\right)\Rightarrow V_{O_2}=0,0625.22,4=1,4\left(l\right)\)

\(n_{H_2O}=n_{H_2}=0,125\left(mol\right)\Rightarrow m_{H_2O}=0,125.18=2,25\left(g\right)\)

Số mol của 2,8 lít khí H₂

n_H2 = \(\dfrac{V}{22,4}\)  = \(\dfrac{2,8}{22,4}\) = 0.125 mol

a. PTHH: 2H₂ + O₂ \(\rightarrow\) 2H₂O

Tỉ lệ:          2        1          2

Mol:     0.125 \(\rightarrow\) 0.1 \(\rightarrow\) 0.125

b. Thể tích khí O₂ ở đktc

 V_O2 = n . 22,4 = 0.1 . 22,4 = 2,24 (l)

Khối lượng H₂O thu được

m_H2O = n . M = 0.125 . 18 = 2,25g

a) Ta có PTHH: 2H₂ + O₂ -----> 2H₂O  (1)

b) Biết V_H2 = 2,8 L ⇒  n_H2 = V/22,4= 2,8/22,4=0,125  ( mol)

Theo PT (1) ta có :

n_O2 =1/2 n_H2 = 1/2 . 0,125= 0,0625 ( mol)

Vậy V_O2 = n . 22,4= 0,0625 . 22,4=1,4 (l)

Theo PT (1) ta có :

n_H2O= n_H2 =0,125 (mol)

Vậy m_H2O = n.M= 0,125 . 18=2,25 (g)

Gửi Bạn!

\(\left(a\right)2Al+3H_2O\rightarrow Al_2\left(SO_4\right)_3+3H_2\\ \left(b\right)n_{H_2}=\dfrac{13,44}{22,4}=0,6mol\\ n_{Al}=\dfrac{0,6.2}{3}=0,4mol\\ m_{Al}=0,4.27=10,8g\\ \left(c\right)n_{O_2}=\dfrac{4,8}{32}=0,15mol\\ 4Al+3O_2\underrightarrow{t^0}2Al_2O_3\\ \Rightarrow\dfrac{0,4}{4}>\dfrac{0,15}{3}\Rightarrow Al.dư\\ n_{Al_2O_3}=\dfrac{0,15.2}{3}=0,1mol\\ m_{oxit}=m_{Al_2O_3}=0,1.102=10,2g\)

a: \(2Al+3H_2SO_4\rightarrow1Al_2\left(SO_4\right)_3+3H_2\uparrow\)

    0,4           0,6                0,2             0,6

b: \(n_{H_2}=\dfrac{13.44}{22.4}=0.6\left(mol\right)\)

=>\(n_{Al}=0.4\left(mol\right)\)

\(m_{Al}=0.4\cdot27=10.8\left(g\right)\)

c: \(4Al+3O_2\rightarrow2Al_2O_3\)

0,4                      0,2

\(m_{Al_2O_3}=0.2\left(27\cdot2+16\cdot3\right)=0.2\cdot102=20.4\left(g\right)\)

\(n_{H_2}=\dfrac{13,44}{22,4}=0,6\left(mol\right)\)

PTHH ;

2Al + 3H2SO4 --> Al2(SO4)3 + 3H2↑

  0,4           0,6               0,2           0,6

4Al + 3O2 ---> 2Al2O3

0,2       0,15          0,1 

\(n_{O_2}=\dfrac{4,8}{32}=0,15\left(mol\right)\)

\(\dfrac{0,4}{4}>\dfrac{0,15}{3}\)

--> Tính theo oxi

\(b,m_{Al}=0,4.27=10,8\left(g\right)\)

\(c,m_{Al_2O_3}=0,1.102=10,2\left(g\right)\)

Zn+2HCl->ZnCl2+H2

0,2-----0,4---0,2----0,2

nZn=0,2 mol

=>m Hcl=0,4.36,5=14,6g

m muối=0,2.136=27,2g

=>VH2=0,2.22,4=4,48l

`Zn + 2HCl -> ZnCl_2 + H_2` `\uparrow`

`n_(Zn) = 13/65 = 0,2 mol`.

`n_(HCl) = 0,4 mol`.

`m_(HCl) = 0,4 xx 36,5 = 14,6g`.

c, `m_(ZnCl_2) = 0,2 xx 127 = 25,4 g`.

`d, V_(H_2) = 0,2 xx 22,4 = 4,48l`.