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\(m_{dd.HCl}=1,08.150=162\left(g\right)\)
\(n_{CO_2}=\dfrac{3,7185}{24,79}=0,15\left(mol\right)\)
\(RCO_3+2HCl\rightarrow RCl_2+H_2O+CO_2\)
0,15<----------------0,15<-----------0,15
Có: \(R+60=\dfrac{12,6}{0,15}\Rightarrow R=24\left(g/mol\right)\)
a. Kim loại R là Magie (Mg)
b. \(C\%_{MgCl_2}=\dfrac{0,15.95.100\%}{12,6+162-0,15.44}=8,48\%\)
c. \(n_{AgCl}=\dfrac{53,8125}{143,5}=0,375\left(mol\right)\)
\(MgCl_2+2AgNO_3\rightarrow2AgCl+Mg\left(NO_3\right)_2\)
0,15-------------------->0,3
Vì \(n_{AgCl}=0,3\left(mol\right)< 0,375\left(mol\right)_{theo.đề}\) \(\Rightarrow\) HCl dư
\(HCl+AgNO_3\rightarrow AgCl+HNO_3\)
0,075<------------0,075
\(CM_{HCl.đem.dùng}=\dfrac{0,075}{0,15}=0,5M\)
\(n_{H_2}=\dfrac{2,24}{22,4}=0,1(mol)\\ a,Zn+2HCl\to ZnCl_2+H_2\\ b,n_{ZnCl_2}=0,1(mol)\\ \Rightarrow m_{ZnCl_2}=0,1.136=13,6(g)\\ c,n_{Zn}=0,1(mol)\\ \Rightarrow \%_{Zn}=\dfrac{0,1.65}{20}.100\%=32,5\%\\ \Rightarrow \%_{Ag}=100\%-32,5\%=67,5\%\)
\(a)n_{H_2}=\dfrac{2,24}{22,4}=0,1mol\\
Fe+2HCl\rightarrow FeCl_2+H_2\)
0,1 0,2 0,1 0,1
\(n_{Fe_2O_3}=\dfrac{21,6-56.0,1}{160}=0,1mol\\
Fe_2O_3+6HCl\rightarrow2FeCl_3+3H_2\)
0,1 0,6 0,2 0,3
\(V_{ddHCl}=\dfrac{0,2+0,6}{1}=0,8l\\
b.C_{M_{FeCl_2}}=\dfrac{0,1}{0,8}=0,125M\\
C_{M_{FeCl_3}}=\dfrac{0,2}{0,8}=0,25M\)
PTHH: \(CaO+2HCl\rightarrow CaCl_2+H_2O\) (1)
\(CaCO_3+2HCl\rightarrow CaCl_2+H_2O+CO_2\uparrow\) (2)
a) Ta có: \(n_{CO_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)=n_{CaCO_3}\)
\(\Rightarrow m_{CaCO_3}=0,2\cdot100=20\left(g\right)\) \(\Rightarrow\%m_{CaCO_3}=\dfrac{20}{25,6}\cdot100\%=78,125\%\)
\(\Rightarrow\%m_{CaO}=21,875\%\)
b) Theo 2 PTHH: \(\left\{{}\begin{matrix}n_{HCl\left(2\right)}=2n_{CaCO_3}=0,4mol\\n_{HCl\left(1\right)}=2n_{CaO}=2\cdot\dfrac{25,6-20}{56}=0,2mol\end{matrix}\right.\)
\(\Rightarrow\Sigma n_{HCl}=0,6mol\) \(\Rightarrow C\%_{HCl}=\dfrac{0,6\cdot36,5}{210\cdot1,05}\cdot100\%\approx9,93\%\)
Chọn C.
\(n_{H_2}=0,4mol\)
\(\Rightarrow n_{HCl}=2n_{H_2}=0,8mol\)
\(C_M=\dfrac{0,8}{\dfrac{400}{1000}}=2M\)
a.Mg + H2SO4 -> MgSO4 + H2
b.\(nH2=\dfrac{4.704}{22.4}=0.21mol\) = nMg
mMg = 0.21\(\times24=5.04g\)
\(\%mMg=\dfrac{5.04\times100}{25}=20.16\%\)
\(\%mAg=100-20.16=79.84\%\)
c.MgSO4 + 2KOH -> K2SO4 + Mg(OH)2
0.21 0.42
H2SO4 + 2KOH -> K2SO4 + H2O
0.04 0.08
\(nH2SO4=\dfrac{9.8\times250}{100\times98}=0.25mol\)
Mà nH2SO4 phản ứng = nH2 = 0.21 mol
\(\Rightarrow nH2SO4dư=0.25-0.21=0.04mol\)
=> nKOH = 0.42 + 0.08 = 0.5mol
\(\Rightarrow CM_{KOH}=\dfrac{0.5}{0.625}=0.8M\)
a) Đặt: nMg=x(mol); nZnO=y(mol)
nH2SO4= 0,2(mol)
PTHH: Mg + H2SO4 -> MgSO4 + H2
x___________x____x_______x(mol)
ZnO + H2SO4 -> ZnSO4 + H2O
y____y______y(mol)
Ta có:
\(\left\{{}\begin{matrix}24x+81y=12,9\\22,4x=4,48\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0,2\\y=0,1\end{matrix}\right.\)
mMg=0,2.24=4,8(g)
%mMg=(4,8/12,9).100=37,209%
=>%mZnO=62,791%
b) nH2SO4=x+y=0,3(mol)
=> \(C\%ddH2SO4=\dfrac{0,3.98}{120}.100=24,5\%\)
\(n_{H_2}=\dfrac{2,24}{22,4}=0,1(mol)\\ a,Fe+2HCl\to FeCl_2+H_2\\ \Rightarrow n_{Fe}=0,1(mol);n_{HCl}=0,2(mol)\\ \Rightarrow m_{Fe}=0,1.56=5,6(g)\\ C_{M_{HCl}}=\dfrac{0,2}{0,25}=0,8M\\ b,m_{dd_{HCl}}=250.1,12=280(g)\\ n_{FeCl_2}=0,1(mol)\\ \Rightarrow C\%_{FeCl_2}=\dfrac{0,1.127}{5,6+280-0,1.2}.100\%=4,45\%\)