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Gọi số mol Na, Zn là a, b
=> 23a + 65b = 14,3
\(n_{H_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)
- Nếu Zn tan hết
PTHH: 2Na + 2H2O --> 2NaOH + H2
______a-------------------->a---->0,5a
2NaOH + Zn --> Na2ZnO2 + H2
__2b<----b-------------------->b
=> \(\left\{{}\begin{matrix}2b\le a\\0,5a+b=14,3\end{matrix}\right.\) => Loại
=> Zn không tan hết => NaOH hết
PTHH: 2Na + 2H2O --> 2NaOH + H2
______a------------------->a---->0,5a
2NaOH + Zn --> Na2ZnO2 + H2
_a--------------------------->0,5a
=> 0,5a + 0,5a = 0,1
=> a = 0,1
=> mNa = 0,1.23 = 2,3 (g)
=> mZn = 14,3 - 2,3 = 12(g)
a)\(n_{H_2}=\dfrac{2,24}{22,4}=0,1mol\)
\(2Na+2H_2O\rightarrow2NaOH+H_2\)
0,2 0,1
\(NaO+H_2O\rightarrow2NaOH\)
b)\(m_{Na}=0,2\cdot23=4,6g\)
\(m_{NaO}=m_{hh}-m_{Na}=40,5-4,6=35,9g\)
c)\(n_{NaO}=\dfrac{35,9}{39}=0,92mol\Rightarrow n_{NaOH}=2n_{NaO}=1,84mol\)
\(\Rightarrow m_{NaOH}=1,84\cdot40=73,6g\)
a, \(n_{H_2}=\dfrac{1,12}{22,4}=0,05\left(mol\right)\)
PT: \(2Na+2H_2O\rightarrow2NaOH+H_2\)
\(Na_2O+H_2O\rightarrow2NaOH\)
Theo PT: \(n_{Na}=2n_{H_2}=0,1\left(mol\right)\Rightarrow m_{Na}=0,1.23=2,3\left(g\right)\)
\(\Rightarrow m_{Na_2O}=8,5-2,3=6,2\left(g\right)\)
b, \(n_{Na_2O}=\dfrac{6,2}{62}=0,1\left(mol\right)\)
Theo PT: \(n_{NaOH}=n_{Na}+2n_{Na_2O}=0,3\left(mol\right)\Rightarrow m_{NaOH}=0,3.40=12\left(g\right)\)
\(a,PTHH:2Na+2H_2O\rightarrow2NaOH+H_2\\ 2K+2H_2O\rightarrow2KOH+H_2\\ n_{Na}=\dfrac{4,6}{23}=0,2\left(mol\right);n_K=\dfrac{3,9}{39}=0,1\left(mol\right)\\ b,n_{H_2\left(tổng\right)}=\dfrac{1}{2}.\left(n_{Na}+n_K\right)=\dfrac{0,2+0,1}{2}=0,15\left(mol\right)\\ V_{H_2\left(đktc\right)}=0,2.22,4=4,48\left(l\right)\)
\(2Na+2H_2O\rightarrow2NaOH+H_2\\ Na_2O+H_2O\rightarrow2NaOH\\ n_{H_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\\ n_{Na}=2.0,3=0,6\left(mol\right)\\ a,m_{Na}=0,6.23=13,8\left(g\right)\\ m_{Na_2O}=26,2-13,8=12,4\left(g\right)\\b, n_{Na_2O}=\dfrac{12,4}{62}=0,2\left(mol\right)\\ n_{NaOH\left(tổng\right)}=n_{Na}+2.n_{Na_2O}=0,6+\dfrac{12,4}{62}=0,8\left(mol\right)\\ m_{c.tan}=m_{NaOH}=0,8.40=32\left(g\right)\\ c,m_{ddNaOH}=m_{hh}+m_{H_2O}-m_{H_2}=26,2+200-0,3.2=225,6\left(g\right)\\ C\%_{ddNaOH}=\dfrac{32}{225,6}.100\approx14,185\%\)
a)
\(2Al + 6HCl \to 2AlCl_3 + 3H_2\\ Fe + 2HCl \to FeCl_2 + H_2\\ b)\\ n_{Al} = a(mol) ; n_{Fe} = b(mol) \Rightarrow 27a + 56b =16,6(1)\\ n_{H_2} = 1,5a + b = \dfrac{11,2}{22,4} = 0,5(2)\\ (1)(2)\Rightarrow a = 0,2 ; b = 0,2\\ \Rightarrow m_{Al} = 0,2.27 = 5,4(gam)\ ;\ m_{Fe} = 0,2.56 = 11,2(gam)\)
a) nH2=0,05(mol)
Na + H2O -> NaOH + 1/2 H2
0,1_______________0,05(mol)
Na2O + H2O -> 2 NaOH
b) => mNa=0,1.23=2,3(g)
=>nNa2O= 14,7 - 2,3= 12,4(g)
nH2=\(\dfrac{1,12}{22,4}\) =0,05 ( mol )
2Na + 2H2O → 2NaOH + H2
0,1 0,1 0,1 0,05 ( mol)
Na2O + H2O → 2NaOH
b) mNa= n.M= 0,1.23= 2,3 (g)
⇒ mNa2O= 14,7 - 2,3= 12,4 ( g)