Cho 6,5 gam Zn tác dụng với dung dịch HCL 2M vừa đủ
a. Viết PTHH
b. Tính thể tích dung dịch HCL 2M đã dùng
c. Cho khí hidro ở trên khử sắt (III) thu được 3g sắt. Tính hiệu suất phản ứng
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a, PT: \(Zn+2HCl\rightarrow ZnCl_2+H_2\)
b, Ta có: \(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\)
Theo PT: \(n_{H_2}=n_{Zn}=0,1\left(mol\right)\Rightarrow V_{H_2}=0,1.22,4=2,24\left(l\right)\)
c, PT: \(Fe_2O_3+3H_2\underrightarrow{t^o}2Fe+3H_2O\)
Theo PT: \(n_{Fe}=\dfrac{2}{3}n_{H_2}=\dfrac{1}{15}\left(mol\right)\Rightarrow m_{Fe}=\dfrac{1}{15}.56=\dfrac{56}{15}\left(g\right)\)
a: \(n_{Fe}=\dfrac{11.2}{56}=0.2\left(mol\right)\)
\(Fe+2HCl\rightarrow FeCl_2+H_2\uparrow\)
0,2 0,4 0,2 0,2
\(V_{H_2}=0,2\cdot22,4=4,48\left(lít\right)\)
b: \(\dfrac{n_{HCl}}{V_{HCl}}=2\)
=>\(\dfrac{0.4}{V_{HCl}}=2\)
=>\(V_{HCl}=\dfrac{0.4}{2}=0.2\left(lít\right)\)
c: \(C_M=\dfrac{n}{V}=\dfrac{0.2}{0.2}=1\)
Bài 3:
\(n_{H_2}=\dfrac{8,96}{22,4}=0,4\left(mol\right)\)
a, PTHH: Fe3O4 + 4H2 --to--> 3Fe + 4H2O
0,1<------0,4
Zn + 2HCl ---> ZnCl2 + H2
0,4<-------------------------0,4
b, mFe3O4 = 0,1.232 = 23,2 (g)
c, mZn = 0,4.65 = 26 (g)
Bài 4:
\(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\)
a, PTHH: Zn + 2HCl ---> ZnCl2 + H2
0,1---->0,2---------------->0,1
b, VH2 = 0,1.22,4 = 2,24 (l)
c, \(C_{M\left(HCl\right)}=\dfrac{0,2}{0,2}=1M\)
a) Fe + 2HCl --> FeCl2 + H2
b) \(n_{Fe}=\dfrac{8,4}{56}=0,15\left(mol\right)\)
PTHH: Fe + 2HCl --> FeCl2 + H2
0,15-->0,3---->0,15-->0,15
=> VH2 = 0,15.22,4 = 3,36 (l)
c) \(m_{dd.HCl}=\dfrac{0,3.36,5}{7,3\%}=150\left(g\right)\)
\(n_{Fe}=\dfrac{8,4}{56}=0,15\left(mol\right)\\
pthh:Fe+2HCl\rightarrow FeCl_2+H_2\)
0,15 0,3 0,15
\(V_{H_2}=0,15.22,4=3,36l\\
m_{\text{dd}HCl}=\dfrac{100.\left(0,3.36,5\right)}{7,3}=150g\)
a) \(n_{Mg}=\dfrac{6}{24}=0,25\left(mol\right)\)
PTHH: Mg + H2SO4 --> MgSO4 + H2
0,25----------------------->0,25
=> VH2 = 0,25.22,4 = 5,6 (l)
b)
\(n_{Fe_2O_3}=\dfrac{32}{160}=0,2\left(mol\right)\)
PTHH: Fe2O3 + 3H2 --to--> 2Fe + 3H2O
Xét tỉ lệ: \(\dfrac{0,2}{1}>\dfrac{0,25}{3}\) => H2 hết
PTHH: Fe2O3 + 3H2 --to--> 2Fe + 3H2O
0,25----->\(\dfrac{1}{6}\)
=> \(m_{Fe}=\dfrac{1}{6}.56=\dfrac{28}{3}\left(g\right)\)
a) PTHH: \(Fe+2HCl\rightarrow FeCl_2+H_2\uparrow\)
b) Ta có: \(n_{HCl}=0,05\cdot0,3=0,015\left(mol\right)\)
\(\Rightarrow n_{Fe}=0,0075\left(mol\right)\) \(\Rightarrow m_{Fe}=0,0075\cdot56=0,42\left(g\right)\)
c+d) Theo PTHH: \(n_{FeCl_2}=n_{H_2}=n_{Fe}=0,0075\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}V_{H_2}=0,0075\cdot22,4=0,168\left(l\right)\\m_{FeCl_2}=0,0075\cdot127=0,9525\left(g\right)\end{matrix}\right.\)
\(n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right)\)
a.
\(Fe+2HCl\rightarrow FeCl_2+H_2\)
\(V_{H_2}=24,79.0,2=4,958\left(l\right)\)
b.
\(n_{HCl}=2.n_{Fe}=0,4\left(mol\right)\\ CM_{HCl}=\dfrac{0,4}{0,2}=2M\)
1:
a) \(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\)
PTHH: \(Zn+H_2SO_4\rightarrow ZnSO_4+H_2\uparrow\)
______0,2------>0,2------------------->0,2_____(mol)
=> \(V_{H_2}=0,2.22,4=4,48\left(l\right)\)
b) \(V_{ddH_2SO_4}=\dfrac{0,2}{1}=0,2\left(l\right)\)
2:
a)
\(n_{HCl}=2.0,2=0,4\left(mol\right)\)
PTHH: \(Mg+2HCl\rightarrow MgCl_2+H_2\uparrow\)
______0,2<------0,4------------------>0,2______(mol)
=> \(m_{Mg}=0,2.24=4,8\left(g\right)\)
b) \(V_{H_2}=0,2.22,4=4,48\left(l\right)\)
nZn = 6.5/65 = 0.1 (mol)
Zn + 2HCl => ZnCl2 + H2
0.1.......0.2...................0.1
VddHCl = 0.2/2 = 0.1 (l)
nFe = 3/56 (mol)
Fe2O3 + 3H2 -to-> 2Fe + 3H2O
.................9/112........3/56
H% = 9/112 / 0.1 * 100% = 80.35%
a) Zn + 2HCl $\to$ ZnCl2 + H2
b) n Zn = 6,5/65 = 0,1(mol)
Theo PTHH : n HCl = 2n Zn = 0,2(mol)
=> V dd HCl = 0,2/2 = 0,1(lít)
c) n Fe = 3/56 (mol)
Fe2O3 + 3H2 $\xrightarrow{t^o}$ 2Fe + 3H2O
Theo PTHH :
n H2 = 3/2 n Fe = 9/112(mol)
Vậy :
H = $\dfrac{ \dfrac{9}{112} }{0,1}$ .100% = 80,36%