\(Đặt.kim.loại.kiềm:A\\ 2A+2HCl\rightarrow2ACl+H_2\\ m_{muối}-m_{kl}=m_{Cl^-}\\ \Leftrightarrow m_{Cl^-}=7,45-3,9=3,55\left(g\right)\\ \Rightarrow n_{HCl}=n_{Cl^-}=\dfrac{3,55}{35,5}=0,1\left(mol\right)\\ \Rightarrow n_A=n_{ACl}=n_{HCl}=0,1\left(mol\right)\\ a,M_A=\dfrac{3,9}{0,1}=39\left(\dfrac{g}{mol}\right)\\ \Rightarrow A\left(I\right):Kali\left(K=39\right)\\ b,n_{H_2}=\dfrac{n_{HCl}}{2}=\dfrac{0,1}{2}=0,05\left(mol\right)\\ \Rightarrow V_{H_2\left(đktc\right)}=0,05.22,4=1,12\left(l\right)\\ c,m_{ddHCl}=\dfrac{0,1.36,5.100}{31,7}=\dfrac{3650}{317}\left(g\right)\\ \Rightarrow V_{ddHCl}=\dfrac{\dfrac{3650}{317}}{1,15}\approx10,012\left(g\right)\)

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 :

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

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

\(n_{NO}=a;n_{N_2O}=b\\ BTe:\dfrac{3m}{27}=3a+b\\ a+b=\dfrac{0,896}{22,4}=0,04mol\\ 30a+44b=0,04.20,25.2=1,62\\ \Rightarrow a=0,01;b=0,03\\ m=0,54\)

\(n_{H_2}=\dfrac{5,6}{22,4}=0,25\left(mol\right)\)

=> n_HCl = 0,5 (mol)

m_muối = m_{kim loại} + m_Cl = 10,2 + 0,5.35,5 = 27,95(g)

nH2​​=22,45,6​=0,25(mol)

=> nHCl = 0,5 (mol)

mmuối = mkim loại + mCl = 10,2 + 0,5.35,5 = 27,95(g)

n_Mg = 0,1(mol)

PTHH: Mg + 2HCl --> MgCl₂ +H₂

n_Mg = n_MgCl2= n_H2 = 0,1(mol)

=> m_muối = 9,5(g) 

_VH2 = 2,24(l)

b) CM_HCl = 0,2/0,1=2(M)

ai làm đc giúp mình với ạ mình sắp phải nộp bài r ạ

a)

$Fe + H_2SO_4 \to FeSO_4 + H_2$
$n_{FeSO_4} = n_{H_2} = \dfrac{11,2}{56} = 0,2(mol)$
$m_{FeSO_4} = 0,2.152 = 30,4(gam)$
$V = 0,2.22,4 = 4,48(lít)$

b)

$n_{H_2SO_4} = n_{Fe} = 0,2(mol)$
$C\%_{H_2SO_4} = \dfrac{0,2.98}{200}.100\% = 9,8\%$

Tham khảo :