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Câu 1
\(a)PTHH:Mg+2HCl\rightarrow MgCl_2+H_2\\
b)200ml=0,2l\\
n_{HCl}=0,2.1=0,2mol\\
n_{H_2}=n_{MgCl_2}=\dfrac{1}{2}n_{H_2}=\dfrac{1}{2}\cdot0,2=0,1mol\\
V_{H_2}=0,1.24,79=2,479l\\
c)C_{M_{MgCl_2}}=\dfrac{0,1}{0,2}=0,5M\)
\(n_{NaOH}=0.2\cdot0.5=0.1\left(mol\right)\)
\(n_{CuSO_4}=0.1\cdot2=0.2\left(mol\right)\)
\(2NaOH+CuSO_4\rightarrow Na_2SO_4+Cu\left(OH\right)_2\)
\(0.1.............0.05...............0.05...........0.05\)
\(m_{Cu\left(OH\right)_2}=0.05\cdot98=4.9\left(g\right)\)
\(C_{M_{Na_2SO_4}}=\dfrac{0.05}{0.2+0.1}=0.167\left(M\right)\)
\(C_{M_{CuSO_4\left(dư\right)}}=\dfrac{0.2-0.05}{0.1}=1.5\left(M\right)\)
2NaOH + CuSO4 → Cu(OH)2 + Na2SO4
n NaOH = 0,2.5 = 1(mol)
n CuSO4 = 0,1.2 = 0,2(mol)
Ta có :
n NaOH / 2 = 0,5 > n CuSO4 / 1 = 0,2 => NaOH dư
n Cu(OH)2 = n CuSO4 = 0,2 mol
=> m A = 0,2.98 = 19,6 gam
n Na2SO4 = n CuSO4 = 0,2 mol
n NaOH pư = 2n CuSO4 = 0,4(mol)
V dd = 0,2 + 0,1 = 0,3(lít)
Suy ra:
CM Na2SO4 = 0,2/0,3 = 0,67M
CM NaOH = (1 - 0,4)/0,3 = 2M
\(n_{Zn}=\dfrac{8,125}{65}=0,125\left(mol\right)\\ m_{HCl}=\dfrac{100.18,25}{100}=18,25\left(g\right)\\
n_{HCl}=\dfrac{18,25}{36,5}=0,5\\ pthh:Zn+2HCl\rightarrow ZnCl_2+H_2\uparrow\)
0,125 0,125 (mol )
\(\Rightarrow V_{H_2}=0,125.22,4=2,8\left(l\right)\\
\)
\(C\%=\dfrac{8,125}{8,125+18,25}.100\%=30,8\%\)
Bài 18:
Ta có: \(n_{Zn}=\dfrac{8,125}{65}=0,125\left(mol\right)\)
\(m_{HCl}=100.18,25\%=18,25\left(g\right)\Rightarrow n_{HCl}=\dfrac{18,25}{36,5}=0,5\left(mol\right)\)
a, PT: \(Zn+2HCl\rightarrow ZnCl_2+H_2\)
b, Xét tỉ lệ: \(\dfrac{0,125}{1}< \dfrac{0,5}{2}\), ta được HCl dư.
Theo PT: \(n_{H_2}=n_{Zn}=0,125\left(mol\right)\)
\(\Rightarrow V_{H_2}=0,125.22,4=2,8\left(g\right)\)
\(m_{H_2}=0,125.2=0,25\left(g\right)\)
c, Theo PT: \(\left\{{}\begin{matrix}n_{ZnCl_2}=n_{Zn}=0,125\left(mol\right)\\n_{HCl\left(pư\right)}=2n_{Zn}=0,25\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow n_{HCl\left(dư\right)}=0,25\left(mol\right)\)
Có: m dd sau pư = 8,125 + 100 - 0,25 = 107,875 (g)
\(\Rightarrow\left\{{}\begin{matrix}C\%_{ZnCl_2}=\dfrac{0,125.136}{107,875}.100\%\approx15,76\%\\C\%_{HCl\left(dư\right)}=\dfrac{0,25.36,5}{107,875}.100\%\approx8,46\%\end{matrix}\right.\)
Bạn tham khảo nhé!
`n_[Zn]=13/65=0,2(mol)`
`Zn + 2HCl -> ZnCl_2 + H_2 \uparrow`
`0,2` `0,4` `0,2` `(mol)`
`a)V_[H_2]=0,2.22,4=4,48(l)`
`b)C%_[HCl]=[0,4.36,5]/150 .100~~9,73%`
a, PT: \(Fe+2HCl\rightarrow FeCl_2+H_2\)
Ta có: \(n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right)\)
\(n_{HCl}=0,5.1=0,5\left(mol\right)\)
Xét tỉ lệ: \(\dfrac{0,2}{1}< \dfrac{0,5}{2}\), ta được HCl dư.
Theo PT: \(\left\{{}\begin{matrix}n_{FeCl_2}=n_{H_2}=n_{Fe}=0,2\left(mol\right)\\n_{HCl\left(pư\right)}=2n_{Fe}=0,4\left(mol\right)\Rightarrow n_{HCl\left(dư\right)}=0,1\left(mol\right)\end{matrix}\right.\)
b, Dung dịch a gồm HCl dư và FeCl2.
PT: \(HCl+NaOH\rightarrow NaCl+H_2O\)
\(FeCl_2+2NaOH\rightarrow Fe\left(OH\right)_{2\downarrow}+2NaCl\)
Theo PT: \(n_{NaOH}=n_{HCl\left(dư\right)}+2n_{FeCl_2}=0,5\left(mol\right)\)
\(\Rightarrow a=C_{M_{NaOH}}=\dfrac{0,5}{0,2}=2,5M\)
c, \(V_{H_2}=0,2.22,4=4,48\left(l\right)\)
Bạn tham khảo nhé!
a) Zn + 2HCl → ZnCl2 + H2↑
b) \(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\)
Theo PT: \(n_{H_2}=n_{Zn}=0,2\left(mol\right)\)
\(\Rightarrow V_{H_2}=0,2\times22,4=4,48\left(l\right)\)
c) Theo PT: \(n_{HCl}=2n_{Zn}=2\times0,2=0,4\left(mol\right)\)
\(\Rightarrow C_{M_{HCl}}=\dfrac{0,4}{0,2}=2\left(M\right)\)