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\(Mg+2HCl\rightarrow MgCl_2+H_2\)
x 2x x x
\(Fe+2HCl\rightarrow FeCl_2+H_2\)
y 2y y y
\(\left\{{}\begin{matrix}x+y=0,5\\24x+56y=23,2\end{matrix}\right.\)
\(\Leftrightarrow x=0,15;y=0,35\)
\(a,m_{Mg}=0,15.24=3,6\left(g\right)\)
\(m_{Fe}=19,6\left(g\right)\)
\(b,m_{HCl}=\left(0,3+0,7\right).36,5=36,5\left(g\right)\)
\(m_{ddHCl}=1,14.200=228\left(g\right)\)
\(C\%=\dfrac{36,5}{228}.100\%=16\%\)
\(a.n_{H_2}=\dfrac{11,2}{22,4}=0,5mol\\ n_{Mg}=a;n_{Fe}=b\\ Mg+2HCl\rightarrow MgCl_2+H_2\\ Fe+2HCl\rightarrow FeCl_2+H_2\\ \Rightarrow\left\{{}\begin{matrix}24a+56b=23,2\\a+b=0,5\end{matrix}\right.\\ \Rightarrow a=0,15;b=0,35mol\\ m_{Mg}=0,15.24=3,6g\\ m_{Fe}=23,2-3,6=19,6g\\ b.m_{HCl}=\left(0,15+0,35\right).2.36,5=36,5g\\ m_{ddHCl}=1,14.200=228g\\ C_{\%HCl}=\dfrac{36,5}{228}\cdot100=16,01\%\)
1)
nNO3(-) trong muối = nNO2 + 3nNO + 8nN2O + 10nN2 = x + 3y + 8z + 10t
m muối = m kim loại + mNO3(-) = a + 62.(x + 3y + 8z + 10t)
vậy chọn đáp án A
2)
nNO3(-) trong muối = 62g => nNO3(-) = 1mol
2Cu(NO3)2 => 2CuO + 4NO2 + O2
4Fe(NO3)3 => 2Fe2O3 + 12NO2 + 3O2
Zn(NO3)2 => 2ZnO + 4NO2 + O2
nNO2 = nNO3(-) = 1 mol
nO2 = nNO2/4 = 1/4 = 0,25mol
=> m chất rắn = m + 62 - 46 - 32.0,25 = m + 8
vậy chọn đáp án A
1.GS có 100g dd $HCl$
=>m$HCl$=100.20%=20g
=>n$HCl$=20/36,5=40/73 mol
=>n$H2$=20/73 mol
Gọi n$Fe$(X)=a mol n$Mg$(X)=b mol
=>n$HCl$=2a+2b=40/73
mdd sau pứ=56a+24b+100-40/73=56a+24b+99,452gam
m$MgCl2$=95b gam
C% dd $MgCl2$=11,79%=>95b=11,79%(56a+24b+99,452)
=>92,17b-6,6024a=11,725
=>a=0,13695 mol và b=0,137 mol
=>C%dd $FeCl2$=127.0,13695/mdd.100%=15,753%
2.Bảo toàn klg=>mhh khí bđ=m$C2H2$+m$H2$
=0,045.26+0,1.2=1,37 gam
mC=mA-mbình tăng=1,37-0,41=0,96 gam
HH khí C gồm $H2$ dư và $C2H6$ không bị hấp thụ bởi dd $Br2$ gọi số mol lần lượt là a và b mol
Mhh khí=8.2=16 g/mol
mhh khí=0,96=2a+30b
nhh khí=0,06=a+b
=>a=b=0,03 mol
Vậy n$H2$=n$C2H6$=0,03 mol
\(\text{Đặt }n_{Al}=x(mol);n_{Fe}=y(mol)\\ \Rightarrow 27x+56y=13,9(1)\\ n_{H_2}=\dfrac{7,84}{22,4}=0,35(mol)\\ a,PTHH:2Al+6HCl\to 2AlCl_3+3H_2(1)\\ Fe+2HCl\to FeCl_2+H_2(2)\\ b,\text{Từ 2 PT: }1,5x+y=0,35(2)\\ (1)(2)\Rightarrow x=0,1(mol);y=0,2(mol)\\ \Rightarrow m_{Al}=0,1.27=2,7(g)\\ m_{Fe}=0,2.56=11,2(g)\)
\(c,n_{HCl(1)}=3n_{Al}=0,3(mol);n_{AlCl_3}=0,1(mol);n_{H_2(1)}=0,15(mol)\\ \Rightarrow m_{dd_{HCl(1)}}=\dfrac{0,3.36,5}{14,6\%}=75(g)\\ \Rightarrow C\%_{AlCl_3}=\dfrac{0,1.133,5}{2,7+75-0,15.2}.100\%=17,25\%\)
\(n_{HCl(2)}=2n_{Fe}=0,4(mol);n_{FeCl_2}=n_{H_2(2)}=n_{Fe}=0,2(mol)\\ \Rightarrow m{dd_{HCl(2)}}=\dfrac{0,4.36,5}{14,6\%}=100(g)\\ \Rightarrow C\%_{FeCl_2}=\dfrac{0,2.127}{11,2+100-0,2.2}.100\%=22,92\%\)
a) 2Al + 6HCl --> 2AlCl3 + 3H2
Fe + 2HCl --> FeCl2 + H2
b) Gọi số mol Al, Fe lần lượt là a,b
=> 27a + 56b = 13,9
\(n_{H_2}=\dfrac{7,84}{22,4}=0,35\left(mol\right)\)
2Al + 6HCl --> 2AlCl3 + 3H2
a----->3a--------->a------->1,5a______(mol)
Fe + 2HCl --> FeCl2 + H2
b------>2b-------->b----->b__________(mol)
=> 1,5a + b = 0,35
=> \(\left\{{}\begin{matrix}a=0,1=>m_{Al}=0,1.27=2,7\left(g\right)\\b=0,2=>m_{Fe}=0,2.56=11,2\left(g\right)\end{matrix}\right.\)
c) nHCl = 3a + 2b = 0,7 (mol)
=> mHCl = 0,7.36,5 = 25,55(g)
=> \(m_{ddHCl}=\dfrac{25,55.100}{14,6}=175\left(g\right)\)
\(m_{dd\left(saupu\right)}=13,9+175-2.0,35=188,2\left(g\right)\)
\(\left\{{}\begin{matrix}m_{AlCl_3}=0,1.133,5=13,35\left(g\right)\\m_{FeCl_2}=0,2.127=25,4\left(g\right)\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}C\%\left(AlCl_3\right)=\dfrac{13,35}{188,2}.100\%=7,1\%\\C\%\left(FeCl_2\right)=\dfrac{25,4}{188,2}.100\%=13,5\%\end{matrix}\right.\)
a, gọi a= nFe
b= nFeO
=> 56a + 72b= 12,8 (1)
Fe +H2SO4 -> FeSO4 +H2
a b b a
FeO +H2SO4 -> FeSO4 +H2O
b b b
a=nH2 = 2,24/22,4= 0,1 mol
từ (1) => b= 0,1
mFe= 56.0,1=5,6(g)
m FeO = 72.0,1= 7,2(g)
b, nH2SO4 (bđ) = 0,25 mol
nH2SO4 pứ = a+b =0,2 mol
=> nH2SO4 dư = 0,25-0,2=0,05 mol
2NaOH +H2SO4 -> Na2SO4 +2H2O
0,1 0,05
V(NaOH)= 0,1/ 1= 0,1 lit =100ml
15
a)\(Fe+H2SO4-->FeSO4+H2\)
\(n_{H2}=\frac{33,6}{22,4}=1,5\left(mol\right)\)
\(n_{Fe}=n_{H2}=1,5\left(mol\right)\)
\(m_{Fe}=1,5.56=84\left(g\right)\)
b)\(n_{FeSO4}=n_{H2}=1,5\left(mol\right)\)
\(m=m_{FeSO4}=1,5.152=228\left(g\right)\)
c)\(n_{H2SO4}=n_{H2}=1,5\left(mol\right)\)
\(C_{M\left(H2SO4\right)}=\frac{1,5}{0,5}=3\left(M\right)\)
16.
n\(_{H2}=\frac{2,24}{22,4}=0,1\left(mol\right)\)
Gọi \(n_{Mg}=x,n_{Fe}=y\)
\(Mg+2HCl--.MgCl2+H2\)
x-------------------------x----------x(mol)
\(Fe=2HCl-->FeCl2+H2\)
y----------------------------y------y(mol)
Theo bài ta có hpt
\(\left\{{}\begin{matrix}24x+56y=4\\x+y=0,1\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=0,05\\y=0,05\end{matrix}\right.\)
\(m_{MgCl2}=0,05.95=4,75\left(g\right)\)
\(m_{FeCl2}=0,05.127=6,35\left(g\right)\)
17.
\(n_{H2}=\frac{13,44}{22,4}=0,6\left(mol\right)\)
\(Fe+2HCl--.FeCl2+H2\)
x----------------------------------x(mol)
\(2Al+6HCl--.2AlCl3+3H2\)
y----------------------------------------1,5y(mol)
theo bài ta có hpt
\(\left\{{}\begin{matrix}56x+27y=22,2\\x+1,5y=0,6\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=0,3\\y=0,2\end{matrix}\right.\)
\(\%m_{Fe}=\frac{0,3.56}{22,2}.100\%=75,68\%\%\)
\(\%m_{Al}=100-75,68=24,32\%\)
18.
\(Mg+2HCl--.MgCl2+H2\)
\(Fe+2HCl--.FeCl2+H2\)
Chất rắn k tan là Cu = 2,54(g)
=>\(m_{Mg+Fe}=10,54-02,54=10\left(g\right)\)
\(n_{H2}=\frac{4,48}{22,4}=0,2\left(mol\right)\Rightarrow m_{H2}=0,4\left(g\right)\)
\(n_{HCl}=n_{H2}=0,4\left(mol\right)\Rightarrow m_{HCl}=0,4.36,5=14,6\left(g\right)\)
\(m=m_{Fe+Mg}+m_{HCl}-m_{H2}=10+14,6-0,4=24,2\left(g\right)\)
\(a.n_{H_2}=\dfrac{2,24}{22,4}=0,1mol\\ Fe+2HCl\rightarrow FeCl_2+H_2\)
0,1 0,2 0,1 0,1
\(m_{Fe}=0,1.56=5,6g\\ m_{FeO}=13,6-5,6=8g\)
\(b.n_{FeO}=\dfrac{8}{72}=\dfrac{1}{9}mol\)
\(FeO+2HCl\rightarrow FeCl_2+H_2O\)
\(\dfrac{1}{9}\) \(\dfrac{2}{9}\) \(\dfrac{1}{9}\)
\(C_{M_{HCl}}=\dfrac{0,2+\dfrac{2}{9}}{0,2}=\dfrac{19}{9}M\)
\(c.m_{FeCl_2}=\left(0,1+\dfrac{1}{9}\right)127=26,81g\)
cảm ơn bn