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Ta có: \(n_{H_2}=\dfrac{74,37}{24,79}=3\left(mol\right)\)
PT: \(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
a, \(n_{Al}=\dfrac{2}{3}n_{H_2}=2\left(mol\right)\)
\(\Rightarrow m_{Al}=2.27=54\left(g\right)\)
b, \(n_{H_2SO_4}=n_{H_2}=3\left(mol\right)\)
\(\Rightarrow m_{H_2SO_4}=3.98=294\left(g\right)\)
PTHH: \(2Al\left(OH\right)_3+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+6H_2O\)
Ta có: \(n_{Al\left(OH\right)_3}=\dfrac{7,8}{78}=0,1\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{H_2SO_4}=0,15mol\\n_{Al_2\left(SO_4\right)_3}=0,05mol\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{H_2SO_4}=0,15\cdot98=14,7\left(g\right)\\m_{Al_2\left(SO_4\right)_3}=0,05\cdot342=17,1\left(g\right)\end{matrix}\right.\)
a)
\(2Al + 3H_2SO_4 \to Al_2(SO_4)_3 + 3H_2\)
b)
\(n_{H_2} = \dfrac{6.13,44}{22,4} = 3,6(mol)\)
Theo PTHH :
\(n_{Al} = \dfrac{2}{3}n_{H_2} = 2,4(mol)\\ \Rightarrow m_{Al} = 2,4.27 = 64,8(gam)\)
c)
\(4Al + 3O_2 \xrightarrow{t^o} 2Al_2O_3\)
Theo PT trên :
\(n_{O_2} = \dfrac{3}{4}n_{Al} = 1,8(mol)\\ \Rightarrow V_{O_2} = 1,8.22,4 = 40,32(lít)\)
PTHH: \(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
Ta có: \(n_{Al}=\dfrac{2,7}{27}=0,1\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{H_2SO_4}=0,15\left(mol\right)=n_{H_2}\\n_{Al_2\left(SO_4\right)_3}=0,05\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{H_2SO_4}=0,15\cdot98=14,7\left(g\right)\\m_{Al_2\left(SO_4\right)_3}=0,05\cdot342=17,1\left(g\right)\\V_{H_2}=0,15\cdot22,4=3,36\left(l\right)\end{matrix}\right.\)
a) \(n_{Al}=\dfrac{2,7}{27}=0,1\left(mol\right)\)
PTHH: 2Al + 3H2SO4 --> Al2(SO4)3 + 3H2
______0,1--->0,15-------->0,05------->0,15
=> mH2SO4 = 0,15.98 = 14,7 (g)
b) VH2 = 0,15.22,4 = 3,36 (l)
c) mAl2(SO4)3 = 0,05.342 = 17,1 (g)
Theo định luật bảo toàn khối lượng
⇒ \(m_{Al}+m_{H_2SO_4}=m_{Al_2\left(SO_4\right)_3}+m_{H_2}\)
⇒ \(m_{H_2}=0,3\left(g\right)\)
\(n_{H_2}=\dfrac{m}{M}=\dfrac{0,3}{2}=0,15\left(mol\right)\)
\(V_{H_2\left(đktc\right)}=n.22,4=0,15.22,4=3,36\left(l\right)\)
số phân tử khí H2 trong phản ứng trên
\(=0,15.6.10^{23}=9.10^{22}\)(phân tử)
Theo ĐLBTKL: mAl + mH2SO4 = mAl2(SO4)3 + mH2
=> mH2 = 2,7 + 14,7 - 17,1 = 0,3(g)
\(n_{H_2}=\dfrac{0,3}{2}=0,15\left(mol\right)\)
\(V_{H_2}=0,15.22,4=3,36\left(l\right)\)
Số phân tử H2 = 0,15.6.1023 = 0,9.1023
\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\uparrow\)
\(2:3:1:3\left(mol\right)\)
\(0,1:0,15:0,05:0,15\left(mol\right)\)
\(n_{H_2}=\dfrac{V}{22,4}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)
\(a,m_{Al}=n.M=0,1.27=2,7\left(kg\right)\)
\(b,m_{Al_2\left(SO_4\right)_3}=n.M=0,05.342=17,1\left(g\right)\)
n của Al2(SO4)3 = 0,5
=» m = 0,5 . 342 chứ?
0,05 đâu ra vậy?