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a) nAl=2,7/27=0,1(mol)
nHCl=14,6/36,5= 0,4(mol)
PTHH: 2Al +6 HCl -> 2 AlCl3 +3 H2
Ta có: 0,1/2 < 0,6/4
=> HCl dư, Al hết, tính theo nAl
=> nAlCl3=nAl=0,1(mol)
=> mAlCl3=0,1.133,5=13,35(g)
b) nH2= 3/2. nAl=3/2. 0,1=0,15(mol)
=>V(H2,đktc)=0,15.22,4=3,36(l)
c) mFe2O3(nguyên chất)= 80%. 38,4=30,72(g)
=>nFe2O3= 30,72/160=0,192(mol)
PTHH: Fe2O3 + 3 H2 -to->2 Fe +3 H2O
Ta có: 0,192/1 > 0,15/3
=> H2 hết, Fe2O3 dư, tính theo nH2
=> nFe= 2/3. nH2= 2/3. 0,15=0,1(mol)
=>mFe=0,1.56=5,6(g)
a,\(n_{Al}=\dfrac{2,7}{27}=0,1\left(mol\right);n_{HCl}=\dfrac{14,6}{36,5}=0,4\left(mol\right)\)
PTHH: 2Al + 6HCl → 2AlCl3 + 3H2
Mol: 0,1 0,1 0,15
Tỉ lệ:\(\dfrac{0,1}{2}< \dfrac{0,4}{6}\) ⇒ Al pứ hết,HCl dư
\(\Rightarrow m_{AlCl_3}=0,1.133,5=13,35\left(g\right)\)
b,\(V_{H_2}=0,15.22,4=3,36\left(l\right)\)
c,\(m_{Fe_2O_3\left(tinhkhiét\right)}=38,4.\left(100\%-20\%\right)=30,72\left(g\right)\)
⇒\(n_{Fe_2O_3}=\dfrac{30,72}{160}=0,192\left(mol\right)\)
PTHH: Fe2O3 + 3H2 → 2Fe + 3H2O
Mol : 0,15 0,1
Tỉ lệ:\(\dfrac{0,192}{1}>\dfrac{0,15}{3}\)⇒ Fe2O3 dư,H2 hết
=> mFe = 0,1.56 =5,6 (g)
Ta có: \(n_{H_2}=\dfrac{5,6}{22,4}=0,25\left(mol\right)\)
PT: \(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
a, \(n_{Al}=\dfrac{2}{3}n_{H_2}=\dfrac{1}{6}\left(mol\right)\Rightarrow m_{Al}=\dfrac{1}{6}.27=4,5\left(g\right)\)
b, \(n_{H_2SO_4}=n_{H_2}=0,25\left(mol\right)\Rightarrow C_{M_{H_2SO_4}}=\dfrac{0,25}{0,2}=1,25\left(M\right)\)
c, \(n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{3}n_{H_2}=\dfrac{1}{12}\left(mol\right)\)
\(\Rightarrow m_{Al_2\left(SO_4\right)_3}=\dfrac{1}{12}.342=28,5\left(g\right)\)
\(Zn + H_2SO_4 \rightarrow ZnSO_4 + H_2\)
b)
\(n_{H_2}= \dfrac{2,24}{22,4}= 0,1 mol\)
\(\)Theo PTHH:
\(n_{ZnSO_4}= n_{H_2}= 0,1 mol\)
\(m_{ZnSO_4}= 0,1 . 161=16,1g\)
c)
Theo PTHH:
\(n_{H_2SO_4}= n_{H_2}= 0,1 mol\)
\(\Rightarrow m_{H_2SO_4}= 0,1 . 98= 9,8g\)
\(\Rightarrow m_{dd H_2SO_4}= \dfrac{9,8 . 100}{20}=49g\)
nH2 = \(\frac{1,68}{22,4}\) = 0,075 (mol)
Mg + 2HCl \(\rightarrow\) MgCl2 + H2\(\uparrow\) (1)
0,075 <--------0,075 <--0,075 (mol)
MgO + 2HCl \(\rightarrow\) MgCl2 + H2O (2)
%mMg= \(\frac{0,075.24}{5,8}\) . 100% = 31,03 %
%m MgO = 68,97%
nMgO = \(\frac{5,8-0,075.24}{40}\) = 0,1 (mol)
Theo pt(2) nMgCl2 = nMgO= 0,1 (mol)
mdd sau pư = 5,8 + 194,35 - 0,075.2 = 200 (g)
C%(MgCl2) = \(\frac{95\left(0,075+0,1\right)}{200}\) . 100% = 8,3125%
a, \(n_{H_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)
PTHH: Fe + 2HCl → FeCl2 + H2
Mol: 015 0,3 0,15 0,15
b, \(m_{Fe}=0,15.56=8,4\left(g\right)\)
\(m_{FeCl_2}=0,15.127=19,05\left(g\right)\)
c, \(C_{M_{ddHCl}}=\dfrac{0,3}{0,05}=6M\)
a) \(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\)
\(m_{H_2SO_4}=147.10\%=14,7\left(g\right)\Rightarrow n_{H_2SO_4}=\dfrac{14,7}{98}=0,15\left(mol\right)\)
PTHH: Zn + H2SO4 → ZnSO4 + H2
Mol: 0,1 0,1 0,1 0,1
Ta có: \(\dfrac{0,1}{1}< \dfrac{0,15}{1}\) ⇒ Zn hết, H2SO4 dư
b) \(V_{H_2}=0,1.22,4=2,24\left(l\right)\)
c) mdd sau pứ = 6,5 + 147 - 0,1.2 = 153,3 (g)
\(C\%_{ddZnSO_4}=\dfrac{0,1.161.100\%}{153,3}=10,502\%\)
\(C\%_{ddH_2SO_4dư}=\dfrac{\left(0,15-0,1\right).98.100\%}{153,3}=3,196\%\)
PTHH: \(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\uparrow\)
Ta có: \(\left\{{}\begin{matrix}n_{Al}=\dfrac{4,05}{27}=0,15\left(mol\right)\\n_{H_2SO_4}=\dfrac{294\cdot10\%}{98}=0,3\left(mol\right)\end{matrix}\right.\)
Xét tỉ lệ: \(\dfrac{0,15}{2}< \dfrac{0,3}{3}\) \(\Rightarrow\) Axit còn dư
\(\Rightarrow\left\{{}\begin{matrix}n_{Al_2\left(SO_4\right)_3}=0,075\left(mol\right)=n_{H_2SO_4\left(dư\right)}\\n_{H_2}=0,225\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}V_{H_2}=0,225\cdot22,4=5,04\left(l\right)\\m_{Al_2\left(SO_4\right)_3}=0,075\cdot342=25,65\left(g\right)\\m_{H_2SO_4\left(dư\right)}=0,075\cdot98=7,35\left(g\right)\\m_{H_2}=0,225\cdot2=0,45\left(g\right)\end{matrix}\right.\)
Mặt khác: \(m_{dd}=m_{Al}+m_{ddH_2SO_4}-m_{H_2}=297,6\left(g\right)\)
\(\Rightarrow\left\{{}\begin{matrix}C\%_{Al_2\left(SO_4\right)_3}=\dfrac{25,65}{297,6}\cdot100\%\approx8,62\%\\C\%_{H_2SO_4\left(dư\right)}=\dfrac{7,35}{297,6}\cdot100\%\approx4,47\%\end{matrix}\right.\)