Hòa tan 8g CuO vào 200g dd HCl 7,3%
A)PTHH
B)mCuCl2
C) C% chất sau p/ ứng
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a) \(m_{HCl}=200.7,3\%=14,6\left(g\right)\Rightarrow n_{HCl}=\dfrac{14,6}{36,5}=0,4\left(mol\right)\)
PTHH: CuO + 2HCl → CuCl2 + H2O
Mol: 0,2 0,4 0,2
b,\(m_{CuO}=0,2.80=16\left(g\right)\)
c, mdd sau pứ = 16+200 = 216 (g)
\(C\%_{ddCuCl_2}=\dfrac{0,2.135.100\%}{216}=12,5\%\)
\(m_{HCl}=200.7,3\%=14,6\left(g\right)\\ n_{Cl^-}=n_{HCl}=\dfrac{14,6}{36,5}=0,4\left(mol\right)\\ m_{muối}=m_{hh.kim.loại}+m_{Cl^-}=8+0,4.35,5=22,2\left(g\right)\)
a) $Fe + 2HCl \to FeCl_2 + H_2$
b) $n_{Fe} = \dfrac{11,2}{56} = 0,2(mol)$
$n_{HCl} = \dfrac{200.7,3\%}{36,5} = 0,4(mol)$
$Fe + 2HCl \to FeCl_2 + H_2$
Ta thấy : $n_{Fe} : 1 = n_{HCl} : 2$ nên phản ứng vừa đủ
$n_{H_2} = n_{Fe} = 0,2(mol)$
$V_{H_2} = 0,2.22,4 = 4,48(lít)$
c) $m_{dd\ sau\ pư} = 11,2 + 200 - 0,2.2 = 210,8(gam)$
$C\%_{FeCl_2} = \dfrac{0,2.127}{210,8}.100\% = 12,05\%$
\(CuO + 2HCl \rightarrow CuCl_2 + H_2O\)
\(n_{CuO} = \dfrac{8}{80}= 0,1 mol\)
\(m_{HCl}= 100 . 18,25\)%= 18,25g
\(n_{HCl}= \dfrac{18,25}{36,5}=0,5 mol\)
\(CuO + 2HCl \rightarrow CuCl_2 + H_2O\)
Trước pư: 0,1 0,5
PƯ 0,1 0,2 0,1
Sau pư 0 0,3 0,1
Dung dịch sau pư: CuCl2 và HCl dư
\(m_{dd sau pư} = m_{CuO} + m_{dd HCl}=8 +100= 108g\)
C%HCl\(=\dfrac{0,3 . 36,5}{108} . 100\)%= 10,139%
C%CuCl2\(=\dfrac{0,1. 135}{108}.100\)%= 12,5%
a, \(Mg+H_2SO_4\rightarrow MgSO_4+H_2\)
b, \(n_{Mg}=\dfrac{2,4}{24}=0,1\left(mol\right)\)
\(n_{H_2SO_4}=\dfrac{200.8\%}{98}=\dfrac{8}{49}\left(mol\right)\)
Xét tỉ lệ: \(\dfrac{0,1}{1}< \dfrac{\dfrac{8}{49}}{1}\), ta được H2SO4 dư.
Theo PT: \(n_{H_2SO_4\left(pư\right)}=n_{MgSO_4}=n_{H_2}=n_{Mg}=0,1\left(mol\right)\)
\(\Rightarrow m_{H_2SO_4\left(dư\right)}=\left(\dfrac{8}{49}-0,1\right).98=6,2\left(g\right)\)
c, \(C\%_{MgSO_4}=\dfrac{0,1.120}{2,4+200-0,1.2}.100\%\approx5,93\%\)
a) PTHH: \(MgO+2HCl\rightarrow MgCl_2+H_2O\)
b) Ta có: \(n_{MgO}=\dfrac{8}{40}=0,2\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{MgCl_2}=0,2\left(mol\right)\\n_{HCl}=0,4\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{MgCl_2}=0,2\cdot95=19\left(g\right)\\C\%_{HCl}=\dfrac{0,4\cdot36,5}{200}\cdot100\%=7,3\%\end{matrix}\right.\)
Mặt khác: \(m_{dd\left(sau.p/ứ\right)}=m_{MgO}+m_{ddHCl}=208\left(g\right)\)
\(\Rightarrow C\%_{MgCl_2}=\dfrac{19}{208}\cdot100\%\approx9,13\%\)
c) PTHH: \(MgCl_2+2NaOH\rightarrow2NaCl+Mg\left(OH\right)_2\downarrow\)
Ta có: \(\left\{{}\begin{matrix}n_{MgCl_2}=0,2\left(mol\right)\\n_{NaOH}=\dfrac{200\cdot4\%}{40}=0,2\left(mol\right)\end{matrix}\right.\)
Xét tỉ lệ: \(\dfrac{0,2}{1}>\dfrac{0,2}{2}\) \(\Rightarrow\) NaOH p/ứ hết, MgCl2 còn dư
\(\Rightarrow\left\{{}\begin{matrix}n_{NaCl}=0,2\left(mol\right)\\n_{Mg\left(OH\right)_2}=0,1\left(mol\right)=n_{MgCl_2\left(dư\right)}\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{NaCl}=0,2\cdot58,5=11,7\left(g\right)\\m_{MgCl_2\left(dư\right)}=9,5\left(g\right)\\m_{Mg\left(OH\right)_2}=0,1\cdot58=5,8\left(g\right)\end{matrix}\right.\)
Mặt khác: \(m_{dd\left(sau.p/ứ\right)}=m_{ddA}+m_{ddNaOH}-m_{Mg\left(OH\right)_2}=402,2\left(g\right)\)
\(\Rightarrow\left\{{}\begin{matrix}C\%_{NaCl}=\dfrac{11,7}{402,2}\cdot100\%\approx2,91\%\\C\%_{MgCl_2\left(dư\right)}=\dfrac{9,5}{402,2}\cdot100\%\approx2,36\%\end{matrix}\right.\)
Theo gt ta có: $n_{MgO}=0,2(mol)$
a, $MgO+2HCl\rightarrow MgCl_2+H_2O$
b, Ta có: $n_{HCl}=0,4(mol)\Rightarrow x=7,3$
Bảo toàn khối lượng ta có: $m_{ddA}=208(g)$
$\Rightarrow \%C_{MgCl_2}=9,13\%$
c, Ta có: $n_{NaOH}=0,2(mol)$
$\Rightarrow n_{Mg(OH)_2}=0,1(mol)$
Bảo toàn khối lượng ta có: $m_{ddB}=208+200-0,1.58=402,2(g)$
$\Rightarrow \%C_{MgCl_2}=2,36\%$
PTHH: \(K_2CO_3+2HCl\rightarrow2KCl+CO_2\uparrow+H_2O\)
Ta có: \(n_{HCl}=\dfrac{200\cdot7,3\%}{36,5}=0,4\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{K_2CO_3}=n_{CO_2}=0,2\left(mol\right)\\n_{KCl}=0,4\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{ddK_2CO_3}=\dfrac{0,2\cdot138}{13,8\%}=200\left(g\right)\\V_{CO_2}=0,2\cdot22,4=4,48\left(l\right)\\m_{KCl}=0,4\cdot74,5=29,8\left(g\right)\end{matrix}\right.\)
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