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\(NaOH+HCl\rightarrow NaCl+H_2O\)
\(n_D=n_{HCl}=n_{NaOH}=0,1\cdot0,015=1,5\cdot10^{-3}mol\)
\(C_{M_D}=\dfrac{1,5\cdot10^{-3}}{0,01}=0,15M\)
\(n_{AgCl}=\dfrac{2,87}{143,5}=0,02mol\)
\(AgNO_3+HCl\rightarrow AgCl\downarrow+HNO_3\)
0,02 0,02
\(\Rightarrow C_{M_E}=\dfrac{0,02}{0,08}=0,25M\)
Mà \(\left\{{}\begin{matrix}1\cdot C_{M_A}+3\cdot C_{M_B}=4\cdot0,15=0,6\\3\cdot C_{M_A}+C_{M_B}=4\cdot0,25=10\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}C_{M_A}=0,3M\\C_{M_B}=0,1M\end{matrix}\right.\)
a) Sửa đề: dd H2SO4 9,8%
Ta có: \(n_{H_2}=\dfrac{7,84}{22,4}=0,35\left(mol\right)\) \(\Rightarrow m_{H_2}=0,35\cdot2=0,7\left(g\right)\)
Bảo toàn nguyên tố: \(n_{H_2SO_4}=n_{H_2}=0,35\left(mol\right)\) \(\Rightarrow m_{ddH_2SO_4}=\dfrac{0,35\cdot98}{9,8\%}=350\left(g\right)\)
\(\Rightarrow m_{dd}=m_{KL}+m_{H_2SO_4}-m_{H_2}=361,6\left(g\right)\)
b) Tương tự câu a
Theo gt ta có: $n_{H_2SO_4}=0,2(mol);n_{HCl}=0,15(mol);n_{H_2}=0,25(mol)$
a, Bảo toàn H ta có: $n_{H^+/pu}=0,5(mol)< 0,55(mol)$
Do đó axit còn dư
b, Ta có: $n_{Ba(OH)_2}=0,18(mol);n_{NaOH}=0,3(mol)$
Gọi số mol Mg và Al lần lượt là a;b(mol)
$\Rightarrow 24a+27b=5,1$
Bảo toàn e ta có: $2a+3b=0,5$
Giải hệ ta được $a=b=0,1$
Lượng $OH^-$ tạo kết tủa là $0,18.2+0,3-0,05=0,61(mol)$
Kết tủa gồm 0,18 mol $BaSO_4$; 0,1 mol $Mg(OH)_2$ (Do Al(OH)3 tạo ra bị hòa tan hết)
$\Rightarrow m_{kt}=47,74(g)$
a, \(Fe+2HCl\rightarrow FeCl_2+H_2\)
Ta có: \(n_{Fe}=\dfrac{14}{56}=0,25\left(mol\right)\)
Theo PT: \(\left\{{}\begin{matrix}n_{HCl}=2n_{Fe}=0,5\left(mol\right)\\n_{H_2}=n_{Fe}=0,25\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow V_{H_2}=0,25.24,79=6,1975\left(l\right)\)
\(a=C_{M_{HCl}}=\dfrac{0,5}{0,1}=5\left(M\right)\)
b, Theo PT: \(n_{FeCl_2}=n_{Fe}=0,25\left(mol\right)\)
Ta có: \(n_{AgNO_3}=0,4.1,3=0,52\left(mol\right)\)
PT: \(2AgNO_3+FeCl_2\rightarrow Fe\left(NO_3\right)_2+2AgCl_{\downarrow}\)
______0,5______0,25______0,25________0,5 (mol)
\(AgNO_3+Fe\left(NO_3\right)_2\rightarrow Fe\left(NO_3\right)_3+Ag_{\downarrow}\)
0,02______0,02________0,02________0,02 (mol)
⇒ m = mAgCl + mAg = 0,5.143,5 + 0,02.108 = 73,91 (g)
- Dd sau pư gồm: Fe(NO3)3: 0,02 (mol) và Fe(NO3)2: 0,25 - 0,02 = 0,23 (mol)
\(\Rightarrow\left\{{}\begin{matrix}C_{M_{Fe\left(NO_3\right)_3}}=\dfrac{0,02}{0,1+0,4}=0,04\left(M\right)\\C_{M_{Fe\left(NO_3\right)_2}}=\dfrac{0,23}{0,1+0,4}=0,46\left(M\right)\end{matrix}\right.\)
\(Fe+2HCl->FeCl_2+H_2\\ a.V=\dfrac{14}{56}\cdot22,4=5,6\left(L\right)\\ a=\dfrac{\dfrac{14}{56}\cdot2}{0,1}=5\left(M\right)\\ b.n_{AgNO_3}=0,4\cdot1,3=0,52mol\\ FeCl_2+AgNO_3->Fe\left(NO_3\right)_2+AgCl\\ Fe\left(NO_3\right)_2+AgNO_3->Ag+Fe\left(NO_3\right)_3\\ m=0,25\cdot143,5+0,25\cdot108=62,875\left(g\right)\\ C_{M\left(AgNO_3\right)}=\dfrac{0,02}{0,5}=0,04M\\ C_{M\left(Fe\left(NO_3\right)_3\right)}=\dfrac{0,25}{0,5}=0,5M\)
Ta có: nN2 = 0,22 (mol)
⇒ nNO3- = 10nN2 = 2,2 (mol)
⇒ m muối = mX + mNO3- = 31 + 2,2.62 = 167,4 (g)
nHNO3 = 12nN2 = 2,64 (mol)
\(\Rightarrow V_{HNO_3}=\dfrac{2,64}{2}=1,32\left(l\right)=1320\left(ml\right)\)
Ta có:
\(n_{HCl\left(D\right)}=n_{NaOH}=\frac{0,1.15}{1000}=0,0015\left(mol\right)\)
\(PTHH:NaOH+HCl\rightarrow NaCl+H_2O\)
\(AgNO_3+HCl\rightarrow AgCl+HNO_3\)
\(\Rightarrow CM_D=\frac{0,0015}{0,01}=0,15M\)
\(n_{HCl\left(E\right)}=n_{AgCl}=\frac{2,87}{143,5}=0,02\left(mol\right)\)
\(\Rightarrow CM_E=\frac{0,02}{0,08}=0,25M\)
Giải hệ PT:
\(\left\{{}\begin{matrix}3a+b=10\\a+3b=0,6\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}a=0,3\\b=0,1\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}CM_A=0,3M\\CM_B=0,1M\end{matrix}\right.\)
\(n_{H_2}=\dfrac{8,96}{22,4}=0,4\left(mol\right)\\ PTHH:2Al+6HCl\rightarrow2AlCl_3+3H_2\\ Fe+2HCl\rightarrow FeCl_2+3H_2\\ Đặt:n_{Al}=a\left(mol\right);n_{Fe}=b\left(mol\right)\left(a,b>0\right)\\ \Rightarrow\left\{{}\begin{matrix}27a+56b=11\\1,5a+b=0,4\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=0,2\\b=0,1\end{matrix}\right.\\ a,n_{HCl}=2.n_{H_2}=2.0,4=0,8\left(mol\right)\\ \Rightarrow V_{ddHCl}=\dfrac{0,8}{8}=0,1\left(l\right)\\ b,FeCl_2+2AgNO_3\rightarrow Fe\left(NO_3\right)_2+2AgCl\downarrow\\ AlCl_3+3AgNO_3\rightarrow Al\left(NO_3\right)_3+3AgCl\downarrow\\ n_{AgCl}=n_{AgNO_3}=3.n_{AlCl_3}+2.n_{FeCl_2}=3.a+2.b=3.0,2+2.0,1=0,8\left(mol\right)\\ \Rightarrow a=\dfrac{170.0,8}{250}.100=54,4\%\\ b=m_{\downarrow}=m_{AgCl}=0,8.143,5=114,8\left(g\right)\)
Câu 1:
Gọi : nMg=a(mol); nMgO=b(mol) (a,b>0)
a) PTHH: Mg + 2 HCl -> MgCl2 + H2
a________2a_______a______a(mol)
MgO +2 HCl -> MgCl2 + H2O
b_____2b_______b___b(mol)
Ta có hpt:
\(\left\{{}\begin{matrix}24a+40b=8,8\\22,4a=4,48\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=0,2\\b=0,1\end{matrix}\right.\)
=> mMg=0,2.24=4,8(g)
=>%mMg= (4,8/8,8).100=54,545%
=> %mMgO= 45,455%
b) m(muối)=mMg2+ + mCl- = 0,3. 24 + 0,6.35,5=28,5(g)
c) V=VddHCl=(2a+2b)/2=0,3(l)=300(ml)
Câu 2:
Ta có: \(\left\{{}\begin{matrix}n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\\n_{HCl}=0,4\cdot2=0,8\left(mol\right)\end{matrix}\right.\)
PTHH: \(Ca+2HCl\rightarrow CaCl_2+H_2\uparrow\)
0,2____0,4_____0,2____0,2 (mol)
\(CaO+2HCl\rightarrow CaCl_2+H_2O\)
0,2____0,4______0,2____0,2 (mol)
Ta có: \(\left\{{}\begin{matrix}\%m_{Ca}=\dfrac{0,2\cdot40}{0,2\cdot40+0,2\cdot56}\cdot100\%\approx41,67\%\\\%m_{CaO}=58,33\%\\m_{CaCl_2}=\left(0,2+0,2\right)\cdot111=44,4\left(g\right)\end{matrix}\right.\)
Bài 15:
nHCl= 0,4.2,75=1,1(mol)
=> nH+=nCl-=nHCl= 1,1(mol)
m=m(muối)= mCl- + m(hh kim loại)= 35,5.1,1 + 25,3= 64,35(g)
nH2= nH+/2= 1,1/2= 0,55(mol)
=> V=V(H2,đktc)= 0,55.22,4=12,32(l)