Hoà tan hoàn toàn 2,8 gam sắt vào dung dịch axit crohidric 10% a) Viết phương trình phản ứng xảy ra b) Tính khối lượng dung dịch HCl 10% cần dùng
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Câu 15 :
\(n_{Al}=\dfrac{10,8}{27}=0,4\left(mol\right)\)
Pt : \(2Al+6HCl\rightarrow2AlCl_3+3H_2\)
0,4----->1,2------->0,4------>0,6
\(m_{HCl}=1,2.36,5=43,8\left(g\right)\)
\(\Rightarrow m_{ddHCl}=\dfrac{43.8.100\%}{25\%}=175,2\left(g\right)\)
\(m_{ddspu}=10,8+175,2-0,6.2=184,8\left(g\right)\)
\(C\%_{AlCl3}=\dfrac{0,4.133,5}{184,8}.100\%=28,9\%\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) Zn + 2HCl --> ZnCl2 + H2
b) \(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\)
PTHH: Zn + 2HCl --> ZnCl2 + H2
_____0,1--->0,2
=> \(V_{ddHCl}=\dfrac{0,2}{1}=0,2\left(l\right)\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(n_{Mg}=\dfrac{10,8}{24}=0,45\left(mol\right)\\
pthh:Mg+H_2SO_4\rightarrow MgSO_4+H_2\uparrow\)
0,45 0,45 0,45
\(m_{H_2SO_4}=0,45.98=44,1\left(g\right)\\
C\%_{H_2SO_4}=\dfrac{44,1}{176,4}.100\%=25\%\\
V_{H_2}=0,45.22,4=10,08\left(l\right)\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) n Fe = 28/56 = 0,5(mol)
$Fe + 2HCl \to FeCl_2 + H_2$
Theo PTHH :
n HCl = 2n Fe = 1(mol)
=> m dd HCl = 1.36,5/10% = 365(gam)
b)
n FeCl2 = n H2 = n Fe = 0,5(mol)
Suy ra :
V H2 = 0,5.22,4 = 11,2(lít)
m FeCl2 = 0,5.127 = 63,5(gam)
c)
Sau phản ứng:
mdd = m Fe + mdd HCl - m H2 = 28 + 365 - 0,5.2 = 392(gam)
=> C% FeCl2 = 63,5/392 .100% = 16,2%
![](https://rs.olm.vn/images/avt/0.png?1311)
\(a,PTHH:Fe+2HCl\to FeCl_2+H_2\\ b,n_{H_2}=\dfrac{3,36}{22,4}=0,15(mol)\\ \Rightarrow n_{Fe}=0,15(mol)\\ \Rightarrow m_{Fe}=0,15.56=8,4(g)\\ c,n_{HCl}=2n_{H_2}=0,3(mol)\\ \Rightarrow m_{dd_{HCl}}=\dfrac{0,3.36,5}{36,5\%}=30(g)\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Ta có: \(n_{Fe}=\dfrac{2,24}{56}=0,04\left(mol\right)\)
a. PTHH: Fe + 2HCl ---> FeCl2 + H2
b. Theo PT: \(n_{FeCl_2}=n_{H_2}=n_{Fe}=0,04\left(mol\right)\)
=> \(m_{FeCl_2}=0,04.127=5,08\left(g\right)\)
=> \(V_{H_2}=0,04.22,4=0,896\left(lít\right)\)
c. Theo PT: \(n_{HCl}=2.n_{Fe}=2.0,04=0,08\left(mol\right)\)
=> \(m_{HCl}=0,08.36,5=2,92\left(g\right)\)
Ta có: \(C_{\%_{HCl}}=\dfrac{2,92}{m_{dd_{HCl}}}.100\%=5\%\)
=> \(m_{dd_{HCl}}=58,4\left(g\right)\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) Fe + 2HCl --> FeCl2 + H2
b) \(n_{H_2}=\dfrac{1,12}{22,4}=0,05\left(mol\right)\)
PTHH: Fe + 2HCl --> FeCl2 + H2
0,05<-0,1<-----------0,05
=> m = 0,05.56 = 2,8 (g)
c) \(m_{HCl}=0,1.36,5=3,65\left(g\right)\Rightarrow m_{dd.HCl}=\dfrac{3,65.100}{10}=36,5\left(g\right)\)
a) Fe + 2HCl $\to$ FeCl2 + H2
b) n Fe = 2,8/56 = 0,05(mol)
Theo PTHH :
n HCl = 2n Fe = 0,1(mol)
=> m dd HCl = 0,1.36,5/10% = 36,5(gam)
Cảm ơn nha!