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Fe+2HCl->FeCl2+H2
x---2x-----------x
Mg+2HCl->MgCl2+H2
y------2y-----------y
Ta có :
\(\left\{{}\begin{matrix}56x+24y=24\\x+y=\dfrac{13,44}{22,4}\end{matrix}\right.\)
=>x=0,3 mol, y=0,3 mol
=>%m Fe=\(\dfrac{0,3.56}{24}.100\)=70%
=>%m Mg=100-70=30%
=>VHCl=\(\dfrac{0,3.2+0,3.2}{2}\)=0,6l=600ml
b)
XCl2+2AgNO3->2AgCl+X(NO3)2
0,6--------------------1,2mol
=>m AgCl=1,2.143,5=172,2g
Gọi a,b lần lượt là số mol của Al,Mg có trong hỗn hợp ban đầu
\(n_{khí}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)
\(2Al+6HCl\rightarrow2AlCl_3+3H_2\uparrow\)
..a............3a............a.............1,5a......(mol)
\(Mg+2HCl\rightarrow MgCl_2+H_2\uparrow\)
..b...........2b..............b...........b............(mol)
Ta có hệ phương trình: \(\left\{{}\begin{matrix}27a+24b=6,3\\1,5a+b=0,3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=0,1\\b=0,15\end{matrix}\right.\left(mol\right)\)
\(m_{AlCl_3}=133,5.0,1=13,35\left(g\right)\); \(m_{MgCl_2}=95.0,15=14,25\left(g\right)\)
nHCl = 3a+2b = 2(1,5a+b) = 2.0,3 = 0,6 (mol)
\(\Rightarrow V_{HCl}=\dfrac{0,6}{0,4}.1000=1500\left(ml\right)\)\(\Rightarrow m_{ddHCl}=V_{HCl}.d=1500.1,2=1800\left(g\right)\)
\(m_{ddsauPƯ}=m_{hh}+m_{ddHCl}-m_{H_2}\)= 6,3 + 1800 - 2.0,3 = 1805,7 (g)
\(C\%_{AlCl_3}=\dfrac{13,35}{1805,7}.100\approx0,74\%\)
\(C\%_{MgCl_2}=\dfrac{14,35}{1805,7}.100\approx0,79\%\)
a)
Gọi số mol Mg, Al là a, b (mol)
=> 24a + 27b = 26,25 (1)
\(n_{H_2}=\dfrac{30,8}{22,4}=1,375\left(mol\right)\)
PTHH: Mg + 2HCl --> MgCl2 + H2
a-->2a--------->a------>a
2Al + 6HCl --> 2AlCl3 + 3H2
b---->3b------->b------>1,5b
=> a + 1,5b = 1,375 (2)
(1)(2) => a = 0,25 (mol); b = 0,75 (mol)
=> \(\left\{{}\begin{matrix}\%m_{Mg}=\dfrac{0,25.24}{26,25}.100\%=22,857\%\\\%m_{Al}=\dfrac{0,75.27}{26,25}.100\%=77,143\%\end{matrix}\right.\)
b)
nHCl = 2a + 3b = 2,75 (mol)
=> mHCl = 2,75.36,5 = 100,375 (g)
=> \(m_{dd.HCl}=\dfrac{100,375.100}{10}=1003,75\left(g\right)\)
c)
mdd sau pư = 1003,75 + 26,25 - 1,375.2 = 1027,25 (g)
\(\left\{{}\begin{matrix}C\%_{MgCl_2}=\dfrac{0,25.95}{1027,25}.100\%=2,312\%\\C\%_{AlCl_3}=\dfrac{0,75.133,5}{1027,25}.100\%=9,747\%\end{matrix}\right.\)
a, PTHH
\(2Al+6HCl\rightarrow2AlCl_3+3H_2\)
_x_____3x_______x______1,5x
\(Mg+2HCl\rightarrow MgCl_2+H_2\)
_y_____2y_______y_______y
\(n_{H_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)
ta có hệ\(\left\{{}\begin{matrix}27x+24y=6,3\\1,5x+y=0,2\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=0,1\left(mol\right)\\y=0,15\left(mol\right)\end{matrix}\right.\)
Vậy: \(\left\{{}\begin{matrix}\%m_{Al}=\dfrac{0,1\times27}{6,3}=42,86\%\\\%m_{Mg}=100\%-42,86\%=57,14\%\end{matrix}\right.\)
b,\(n_{HCl}=3x+2y=0,6\left(mol\right)\)
thể tích dung dịch HCl cần dùng là:
\(V_{HCl}=\dfrac{n}{C_M}=\dfrac{0,6}{0,4}=1,5\left(l\right)=1500\left(ml\right)\)
6,3 gam hôn hợp \(\left\{{}\begin{matrix}Al:a\left(mol\right)\\Mg:b\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow27a+24b=6,3\)(I)
\(2Al\left(a\right)+6HCl\left(3a\right)--->2AlCl_3\left(a\right)+3H_2\left(1,5a\right)\)
\(Mg\left(b\right)+2HCl\left(2b\right)--->MgCl_2\left(b\right)+H_2\left(b\right)\)
\(n_{H_2}=0,3\left(mol\right)\)
\(\Rightarrow1,5a+b=0,3\)(II)
từ (I) và (II): \(\left\{{}\begin{matrix}27a+24b=6,3\\1,5a+b=0,3\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}a=0,1\\b=0,15\end{matrix}\right.\)
=> Phần trăm khối lượng
\(b)\)
Theo PTHH: \(n_{HCl}=3a+2b=3.0,1+2.0,15=0,6\left(mol\right)\)
\(\Rightarrow V_{ddHCl}=\dfrac{0,6}{0,4}=1,5\left(l\right)=1500\left(ml\right)\)
\(c)\)
Vì phản ứng vùa đủ
\(\Rightarrow\)Dung dịch sau phản ứng: \(\left\{{}\begin{matrix}AlCl_3:0,1\left(mol\right)\\MgCl_2:0,15\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow m_{H_2}=0,3.2=0,6\left(g\right)\)
\(m_{ddHCl}=D_{HCl}.V_{ddHCl}=1,2.1500=1800\left(g\right)\)
\(\Rightarrow m_{ddsau}=6,3+1800-0,6=1805,7\left(g\right)\)
=> Tính được C% mỗi muối