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a)
$2Al +3H_2SO_4 \to Al_2(SO_4)_3 + 3H_2$
b)
$n_{H_2} = n_{H_2SO_4} = \dfrac{300.9,8\%}{98} = 0,3(mol)$
$V_{H_2} = 0,3.22,4 = 6,72(lít)$
c)
$n_{Al_2(SO_4)_3} = \dfrac{1}{3}n_{H_2SO_4} = 0,1(mol)$
$m_{Al_2(SO_4)_3} = 0,1.342 = 34,2(gam)$
d)
$n_{Al} = \dfrac{2}{3}n_{H_2SO_4} = 0,2(mol)$
$m_{dd} = 0,2.27 + 300 - 0,3.2 = 304,8(gam)$
$C\%_{Al_2(SO_4)_3} = \dfrac{34,2}{304,8}.100\% = 11,22\%$
nH2SO4=0,3(mol)
PTHH: 2Al + 3 H2SO4 -> Al2(SO4)3 + 3 H2
a) 0,2_______0,3______0,1______0,3(mol)
b) V(H2,đktc)=0,3.22,4=6,72(l)
c) a=mAl=0,2.27=5,4(g)
=>a=5,4(g)
d) mAl2(SO4)3=342.0,1=34,2(g)
e) mddAl2(SO4)3= 5,4+ 300 - 0,3.2= 304,8(g)
=>C%ddAl2(SO4)3= (34,2/304,8).100=11,22%
mH2SO4=9,8%.300=29,4(g)
=> nH2SO4=0,3(mol)
a) PTHH: 2Al +3 H2SO4 -> Al2(SO4)3 + 3 H2
0,2<-------------0,3----------->0,1------------->0,3(mol)
b) a=mAl=0,2.27=5,4(g)
c) V(H2,đktc)=0,3.22,4=6,72(l)
d) mAl2(SO4)3=0,1.342=34,2(g)
e) mddAl2(SO4)3=mAl+mddH2SO4- mH2= 5,4+300-0,3.2= 304,8(g)
=> C%ddAl2(SO4)3=(34,2/304,8).100=11,22%
a) 2Al+ 3H2SO4→ Al2(SO4)3+ 3H2
(mol) 0,2 0,3 0,1 0,3
b) m H2SO4= 300. 9,8%= 29,4(g)
n H2SO4= \(\dfrac{m}{M}=\dfrac{29,4}{98}=0,3\)(mol)
c) V H2= n.22,4= 0,3.22,4= 6,72(lít)
m H2= n.m= 0,3.2= 0,6(g)
d) m Al2(SO4)3= n.M= 0,1.342= 34,2(g)
e) mAl= n.M= 0,2.27= 5,4(g)
mddsau phản ứng= mAl+ mdd H2SO4- m H2
= 5,4+300-0,6= 304,8(g)
=> C%ddsau phản ứng= \(\dfrac{34,2}{304,8}.100\%=11,22\%\)
\(n_{Fe}=\dfrac{11,2}{56}=0,2mol\)
\(n_{HCl}=2,5.0,2=0,5mol\)
\(Fe+2HCl\rightarrow FeCl_2+H_2\)
0,2 < 0,5 ( mol )
0,2 0,4 0,2 0,2 ( mol )
Chất dư là HCl
\(m_{HCl\left(dư\right)}=\left(0,5-0,4\right).36,5=3,65g\)
\(V_{H_2}=0,2.22,4=4,48l\)
\(C_{M_{FeCl_2}}=\dfrac{0,2}{0,2}=1M\)
\(n_{H_2}=\dfrac{2.24}{22.4}=0.1\left(mol\right)\)
\(2A+2nHCl\rightarrow2ACl_n+nH_2\)
\(\dfrac{0.2}{n}.......................0.1\)
\(M_A=\dfrac{2.4}{\dfrac{0.2}{n}}=12n\left(\dfrac{g}{mol}\right)\)
\(BL:n=2\Rightarrow M=24\)
\(A:Mg\)
\(m_{MgCl_2}=0.1\cdot95=9.5\left(g\right)\)
\(m_{ddHCl}=\dfrac{0.2\cdot36.5}{7.3\%}=100\left(g\right)\)
\(m_{dd}=2.4+100-0.1\cdot2=102.2\left(g\right)\)
\(C\%_{MgCl_2}=\dfrac{9.5}{102.2}\cdot100\%=9.3\%\)
\(n_{Zn}=\dfrac{8,125}{65}=0,125\left(mol\right)\\ m_{HCl}=\dfrac{100.18,25}{100}=18,25\left(g\right)\\
n_{HCl}=\dfrac{18,25}{36,5}=0,5\\ pthh:Zn+2HCl\rightarrow ZnCl_2+H_2\uparrow\)
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!
nAl=0,2(mol)
mHCl=500.10%=50(g) => nHCl=50/36,5=100/73(mol)
PTHH: 2 Al + 6 HCl -> 2 AlCl3 + 3 H2
Vì: 0,2/2 < 100/73:6
=> Al hết, HCl dư, tính theo nAl
a) nH2=3/2. 0,2=0,3(mol) => V(H2,đktc)=0,3.22,4=6,72(l)
b) mHCl(tham gia p.ứ)= 6/2. 0,2 . 36,5= 21,9(g)
c) mddsau= 5,4+500-0,3.2=504,8(g)
mAlCl3=0,2. 133,5= 26,7(g)
mHCl(DƯ)= 50 -21,9=28,1(g)
C%ddAlCl3= (26,7/504,8).100=5,289%
C%ddHCl(dư)= (28,1/504,8).100=5,567%
\(nAl=\dfrac{2,7}{27}=0,1\left(mol\right)\)
\(mHCl=\dfrac{200.7,3\%}{100\%}=14,6\left(g\right)\)
\(nHCl=\dfrac{14,6}{36,5}=0,4\left(mol\right)\)
PTHH:
\(2Al+6HCl\rightarrow2AlCl_2+3H_2\)
2 6 2 3 (mol)
0,1 0,3 0,1 0,15 (mol)
LTL : 0,1 / 2 < 0,4/6
=> Al đủ , HCl dư
1. \(VH_2=0,15.22,4=3,36\left(l\right)\)
2. \(mH_2=0,15.2=0,3\left(g\right)\)
mdd = mAl + mddHCl - mH2 = 2,7 + 200 - 0,3 = 202,4 (g)
\(mH_2SO_{4\left(dưsaupứ\right)}=0,1.98=9,8\left(g\right)\)
\(mAlCl_2=0,1.98=9,8\left(g\right)\)
\(C\%_{ddH_2SO_4}=\dfrac{9,8.100}{202,4}=4,84\%\)
\(C\%_{AlCl_2}=\dfrac{9,8.100}{202,4}=4,84\%\)
mHCl dư sau pứ nha, kh phải mH2SO4 dư sau pứ nha