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$a\big)2Al+3H_2SO_4\to Al_2(SO_4)_3+3H_2$
$b\big)$
$n_{Al}=\dfrac{4,05}{27}=0,15(mol)$
$n_{H_2SO_4}=\dfrac{29,4}{98}=0,3(mol)$
Vì $\dfrac{n_{Al}}{2}<\frac{n_{H_2SO_4}}{3}\to H_2SO_4$ dư
$c\big)$
Theo PT: $n_{H_2}=\dfrac{3}{2}n_{Al}=0,225(mol)$
$\to V_{H_2}=0,225.22,4=5,04(l)$
a. 2Al + 3H2SO4 → Al2(SO4)3 + 3H2
b. nH2SO4 =\(\dfrac{29,4}{98}\)=0,3 mol
Theo phương trình ta có số mol nhôm đã phản ứng là nAl= \(\dfrac{0,3.2}{3}\)= 0,1 mol ==> a = 0,1.27 = 2,7 gam
c. Phản ứng vừa đủ nên cả Al và H2SO4 cùng hết , không có chất nào dư sau phản ứng
2Al + 3H2SO4 -> Al2(SO4)3 + 3H2
nAl = 0,1 => nH2 = 0,15 => VH2 = 0,15 . 22,4 = 3,36 (l)
nH2 = 0,15 => mH2 = 0,3(g)
m dd sau pư = 2,7 + 200 -0,3=202,4 (g)
theo pư => n Al2(SO4)3 = 0,05 => m Al2(SO4)3 = 17,1 => C% = 17,1:202,4 . 100 % = 8,45%
A)
$2Al + 3H_2SO_4 \to Al_2(SO_4)_3 + 3H_2$
B)
n Al = 2,7/27 = 0,1(mol)
Theo PTHH :
n H2 = 3/2 n Al = 0,15(mol)
=> V H2 = 0,15.22,4 = 3,36(lít)
Theo PTHH :
n Al2(SO4)3 = 1/2 n Al = 0,05(mol)
m dd sau pư = m Al + mdd H2SO4 - m H2 = 2,7 + 200 - 0,15.2 = 202,4 gam
Suy ra :
C% Al2(SO4)3 = 0,05.342/202,4 .100% = 8,45%
2Al+3H2SO4->Al2(SO4)3+3H2
0,1----------------------0,075----0,15
n H2=0,15 mol
=>mAl=0,1.27=2,7g
=>m Al2(SO4)3=0,075.342=25,65g
a) PTHH: \(2Al+3H_2SO_2\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
b) \(n_{H_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)
\(n_{Al}=\dfrac{2}{3}.0,15=0,1\left(mol\right)\)
\(m_{Al}=0,1.27=2,7\left(g\right)\)
c) \(n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{2}.0,1=0,05\left(mol\right)\)
\(m_{Al_2\left(SO_4\right)_3}=0,05.342=17,1\left(g\right)\)
Câu 2 :
\(Na+H_2O\rightarrow NaOH+\dfrac{1}{2}H_2\)
\(CuO+H_2\underrightarrow{^{t^0}}Cu+H_2O\)
\(K+H_2O\rightarrow KOH+\dfrac{1}{2}H_2\)
\(4P+5O_2\underrightarrow{^{ }t^0}2P_2O_5\)
\(3Fe+2O_2\underrightarrow{^{t^0}}Fe_3O_4\)
\(Zn+2HCl\rightarrow ZnCl_2+H_2\)
\(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)
\(Zn+H_2SO_4\rightarrow ZnSO_4+H_2\)
Câu 3 :
\(n_{H_2}=\dfrac{2.7}{27}=0.1\left(mol\right)\)
\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
\(0.1...........................0.05.......0.15\)
\(V_{H_2}=0.15\cdot22.4=3.36\left(l\right)\)
\(m_{Al_2\left(SO_4\right)_3}=0.05\cdot342=17.1\left(g\right)\)
\(m_{\text{dung dịch sau phản ứng}}=2.7+200-0.15\cdot2=202.4\left(g\right)\)
\(C\%_{Al_2\left(SO_4\right)_3}=\dfrac{17.1}{202.4}\cdot100\%=8.44\%\)
\(n_{Al}=\dfrac{5,4}{27}=0,2\left(mol\right)\\a, 2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\\ n_{H_2}=n_{H_2SO_4}=\dfrac{3}{2}.0,2=0,3\left(mol\right)\\ b,V_{H_2\left(đktc\right)}=0,3.22,4=6,72\left(l\right)\\ c,n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{2}.0,2=0,1\left(mol\right)\\ m_{Al_2\left(SO_4\right)_3}=0,1.342=34,2\left(g\right)\\ d,C\%_{ddH_2SO_4}=\dfrac{0,3.98}{200}.100\%=14,7\%\\ e,m_{ddmuoi}=5,4+200-0,3.2=204,8\left(g\right)\\ C\%_{ddAl_2\left(SO_4\right)_3}=\dfrac{34,2}{204,8}.100\%\approx16,699\%\)
\(a)2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\\ b)n_{Al}=\dfrac{5,4}{27}=0,2mol\\ 2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
\(0,2-\rightarrow0,3--\rightarrow0,1--\rightarrow0,3\)
\(m_{H_2}=0,3.2=0,6g\\ c)m_{Al_2\left(SO_4\right)_3}=0,1.342=34,2g\\ d)C_{\%H_2SO_4}=\dfrac{0,3.98}{200}\cdot100=14,7\%\\ e)C_{\%Al_2\left(SO_4\right)_3}=\dfrac{34,2}{5,4+200-0,6}\cdot100=16,7\%\)
PTHH: \(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\uparrow\)
Làm gộp các phần còn lại
Ta có: \(n_{Al}=\dfrac{5,4}{27}=0,2\left(mol\right)\) \(\Rightarrow\left\{{}\begin{matrix}n_{Al_2\left(SO_4\right)_3}=0,1mol\\n_{H_2SO_4}=n_{H_2}=0,3mol\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}V_{H_2}=0,3\cdot22,4=6,72\left(l\right)\\m_{Al_2\left(SO_4\right)_3}=0,1\cdot342=34,2\left(g\right)\\m_{H_2SO_4}=0,3\cdot98=29,4\left(g\right)\end{matrix}\right.\)
\(n_{H_2}=\dfrac{2.7}{27}=0.1\left(mol\right)\)
\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
\(0.1..........................0.05............0.15\)
\(V_{H_2}=0.15\cdot22.4=3.36\left(l\right)\)
\(m_{Al_2\left(SO_4\right)_3}=0.05\cdot342=17.1\left(g\right)\)
\(m_{\text{dung dịch sau phản ứng}}=2.7+200-0.15\cdot2=202.4\left(g\right)\)
\(C\%_{Al_2\left(SO_4\right)_3}=\dfrac{17.1}{202.4}\cdot100\%=8.45\%\)
Ta có: \(n_{Al}=\dfrac{2,7}{27}=0,1\left(mol\right)\)
a, PT: \(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
_____0,1____0,15_______0,05_____0,15 (mol)
b, Ta có: \(V_{H_2}=0,15.22,4=3,36\left(l\right)\)
c, Ta có: m dd sau pư = mAl + m dd H2SO4 - mH2 = 2,7 + 200 - 0,15.2 = 202,4 (g)
\(\Rightarrow C\%_{Al_2\left(SO_4\right)_3}=\dfrac{0,05.342}{202,4}.100\%\approx8,45\%\)
Bạn tham khảo nhé!