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1)
$MgO + 2HCl to MgCl_2 + H_2O$
$Mg + 2HCl \to MgCl_2 + H_2$
2)
$n_{Mg} = n_{H_2} = \dfrac{2,24}{22,4} = 0,1(mol)$
$m_{Mg} = 0,1.24 = 2,4(gam)$
$m_{MgO} = 4,4 - 2,4 = 2(gam)$
3)
$n_{HCl} = 2n_{Mg} + 2n_{MgO} = 0,1.2 + \dfrac{2}{40}.2 = 0,3(mol)$
$V_{dd\ HCl} = \dfrac{0,3}{2} = 0,15(lít) = 150(ml)$
Rượu etylic \(C_2H_5OH\)
Axit axetic \(CH_3COOH\)
\(n_{CO_2}=\dfrac{2,24}{22,4}=0,1mol\)
\(2CH_3COOH+Na_2CO_3\rightarrow2CH_3COONa+H_2O+CO_2\uparrow\)
0,2 0,1 0,2 0,1 0,1
\(\%m_{CH_3COOH}=\dfrac{0,2\cdot60}{39,6}\cdot100\%=30,3\%\)
\(\%m_{C_2H_5OH}=100\%-30,3\%=69,7\%\)
a)
\(n_{CO_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)
PTHH: 2CH3COOH + Na2CO3 --> 2CH3COONa + CO2 + H2O
0,2<----------0,1<-------------0,2<-------0,1
=> \(m_{CH_3COOH}=0,2.60=12\left(g\right)\)
\(\%m_{CH_3COOH}=\dfrac{12}{39,6}.100\%=30,3\%\)
\(\%m_{C_2H_5OH}=\dfrac{39,6-12}{39,6}.100\%=69,7\%\)
b) dd sau pư chứa \(\left\{{}\begin{matrix}CH_3COONa:0,2\left(mol\right)\\C_2H_5OH:\dfrac{39,6-12}{46}=0,6\left(mol\right)\end{matrix}\right.\)
\(V_{dd}=\dfrac{0,1}{2}=0,05\left(l\right)\)
=> \(\left\{{}\begin{matrix}C_{M\left(CH_3COONa\right)}=\dfrac{0,2}{0,05}=4M\\C_{M\left(C_2H_5OH\right)}=\dfrac{0,6}{0,05}=12M\end{matrix}\right.\)
\(n_{H_2}=\dfrac{1.12}{22.4}=0.05\left(mol\right)\)
\(MgO+2HCl\rightarrow MgCl_2+H_2O\)
\(Mg+2HCl\rightarrow MgCl_2+H_2\)
\(0.05..............................0.05\)
\(m_{Mg}=0.05\cdot24=1.2\left(g\right)\)
\(m_{MgO}=9.5-1.2=8.3\left(g\right)\)
\(\%Mg=\dfrac{1.2}{9.5}\cdot100\%=12.63\%\)
\(\%MgO=100-12.63=87.36\%\)
Đặt \(n_{Mg}=x(mol);n_{Al}=y(mol)\Rightarrow 24x+27y=7,8(1)\)
\(n_{H_2}=\dfrac{8,96}{22,4}=0,4(mol)\\ PTHH:Mg+2HCl\to MgCl_2+H_2\\ 2Al+6HCl\to 2AlCl_3+3H_2\\ \Rightarrow x+1,5y=0,4(2)\\ (1)(2)\Rightarrow x=0,1(mol);y=0,2(mol)\\ a,m_{Mg}=0,1.24=2,4(g)\\ m_{Al}=7,8-2,4=5,4(g)\\ b,\Sigma n_{HCl}=2x+3y=0,8(mol)\\ \Rightarrow V_{dd_{HCl}}=\dfrac{0,8}{2}=0,4(l)\)
\(c,PTHH:MgCl_2+2NaOH\to Mg(OH)_2\downarrow+2NaCl\\ AlCl_3+3NaOH\to Al(OH)_3\downarrow+3NaCl\\ n_{MgCl_2}=n_{Mg(OH)_2}=x=0,1(mol)\\ n_{Al(OH)_3}=n_{AlCl_3}=y=0,2(mol)\\ \Rightarrow m_{Mg(OH)_2}=0,1.58=5,8(g)\\ m_{Al(OH)_3}=0,2.78=15,6(g)\\ m_{kết tủa}=5,8+15,6=21,4(g)\)
PTHH: \(Mg+2HCl\rightarrow MgCl_2+H_2\uparrow\) (1)
\(MgO+2HCl\rightarrow MgCl_2+H_2O\) (2)
a) Ta có: \(n_{H_2}=\dfrac{22,4}{22,4}=1\left(mol\right)=n_{Mg}\) \(\Rightarrow m_{Mg}=1\cdot24=24\left(g\right)\)
\(\Rightarrow\%m_{Mg}=\dfrac{24}{32}\cdot100\%=75\%\) \(\Rightarrow\%m_{MgO}=25\%\)
b) Theo 2 PTHH: \(\left\{{}\begin{matrix}n_{HCl\left(1\right)}=2n_{Mg}=2mol\\n_{HCl\left(2\right)}=2n_{MgO}=2\cdot\dfrac{32-24}{40}=0,4mol\end{matrix}\right.\)
\(\Rightarrow\Sigma n_{HCl}=2,4mol\) \(\Rightarrow m_{ddHCl}=\dfrac{2,4\cdot36,5}{7,3\%}=1200\left(g\right)\)
c) Theo PTHH: \(\Sigma n_{MgCl_2}=\dfrac{1}{2}\Sigma n_{HCl}=1,2mol\)
\(\Rightarrow\Sigma m_{MgCl_2}=1,2\cdot95=114\left(g\right)\)
Mặt khác: \(m_{H_2}=1\cdot2=2\left(g\right)\)
\(\Rightarrow m_{dd}=m_{hh}+m_{ddHCl}-m_{H_2}=1230\left(g\right)\)
\(\Rightarrow C\%_{MgCl_2}=\dfrac{114}{1230}\cdot100\%\approx9,27\%\)
a,\(n_{H_2}=\dfrac{11,2}{22,4}=0,5\left(mol\right)\)
PTHH: Zn + 2HCl → ZnCl2 + H2
Mol: x x
PTHH: Fe + 2HCl → FeCl2 + H2
Mol: y y
Ta có: \(\left\{{}\begin{matrix}65x+56y=30,7\\x+y=0,5\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0,3\left(mol\right)\\y=0,2\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\%m_{Zn}=\dfrac{0,3.65.100\%}{30,7}=63,52\%;\%m_{Fe}=100\%-63,52\%=36,48\%\)
b,
PTHH: Zn + 2HCl → ZnCl2 + H2
Mol: 0,3 0,6
PTHH: Fe + 2HCl → FeCl2 + H2
Mol: 0,2 0,4
nHCl = 0,6+0,4 = 1 (mol)
\(V_{ddHCl}=\dfrac{1}{2}=0,5\left(l\right)=500\left(ml\right)\)
a. PTHH:
Fe + 2HCl ---> FeCl2 + H2 (1)
Mg + 2HCl ---> MgCl2 + H2 (2)
b. Gọi x, y lần lượt là số mol của Fe và Mg
Ta có: \(n_{H_2}=\dfrac{5,6}{22,4}=0,25\left(mol\right)\)
Theo PT(1): \(n_{H_2}=n_{Fe}=x\left(mol\right)\)
Theo PT(2): \(n_{H_2}=n_{Mg}=y\left(mol\right)\)
\(\Rightarrow x+y=0,25\) (*)
Theo đề, ta lại có: 56x + 24y = 8,25 (**)
Từ (*) và (**), ta có HPT:
\(\left\{{}\begin{matrix}x+y=0,25\\56x+24y=8,25\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\approx0,07\\y\approx0,18\end{matrix}\right.\)
=> \(m_{Fe}=0,07.56=3,92\left(g\right)\)
=> \(\%_{m_{Fe}}=\dfrac{3,92}{8,25}.100\%=47,52\%\)
\(\%_{m_{Mg}}=100\%-47,52\%=52,48\%\)
$n_{H_2} = \dfrac{1,792}{22,4} = 0,08(mol)$
$n_{HCl} = 0,2(mol)$
$2Na + 2H_2O \to 2NaOH + H_2$
$Na_2O + H_2O \to 2NaOH$
$NaOH + HCl \to NaCl + H_2O$
Theo PTHH :
$n_{Na} = 2n_{H_2} = 0,16(mol)$
$2n_{Na_2O} + n_{Na} = n_{NaOH} = n_{HCl} = 0,2$
$\Rightarrow n_{Na_2O} = 0,02(mol)$
$\%m_{Na} = \dfrac{0,16.23}{5}.100\% = 73,6\%$
$\%m_{Na_2O} = \dfrac{0,02.62}{5}.100\% = 24,8\%$
Anh ơi!