BTKL: \(n_{Fe}+m_{HCl}=m_{FeCl_2}+m_{H_2}\)

\(\Rightarrow m_{HCl}=12,7+0,2-5,6=7,3(g)\)

Chọn B

Câu 2 : 

$a) Mg + 2HCl \to MgCl_2 + H_2$

$n_{HCl} = 0,2.1 = 0,2(mol)$
Theo PTHH : $n_{H_2} = n_{MgCl_2} = \dfrac{1}{2}n_{HCl} = 0,1(mol)$
$V_{H_2} = 0,1.22,4 = 2,24(lít)$

$b) m_{MgCl_2} = 0,1.95 = 9,5(gam)$

Câu 3 : 

a) $Fe + H_2SO_4 \to FeSO_4 + H_2$

Theo PTHH : 

$n_{H_2SO_4} = n_{H_2} = n_{Fe} = \dfrac{5,6}{56} = 0,1(mol)$
$C\%_{H_2SO_4} = \dfrac{0,1.98}{500}.100\% = 1,96\%$

b)

$V_{H_2} = 0,1.22,4 = 2,24(lít)$
c)

$2H_2 + O_2 \xrightarrow{t^o} 2H_2o$
$V_{O_2} = \dfrac{1}{2}V_{H_2} = 1,12(lít)$

a) nFe=0,1(mol); nHCl=0,4(mol)

PTHH: Fe + 2 HCl -> FeCl2 + H2

Ta có: 0,1/1 < 0,4/2

=> Fe hết, HCl dư, tish theo nFe.

b) nH2=nFeCl2=Fe=0,1(mol)

=> V(H2,đktc)=0,1.22,4=2,24(l)

c) mFeCl2=127.0,1=12,7(g)

a) nFe=0,1(mol); nHCl=0,4(mol) PTHH: Fe + 2 HCl -> FeCl2 + H2 Ta có: 0,1/1 < 0,4/2 => Fe hết, HCl dư, tish theo nFe. b) nH2=nFeCl2=Fe=0,1(mol) => V(H2,đktc)=0,1.22,4=2,24(l) c) mFeCl2=127.0,1=12,7(g)

\(M + 2HCl \to MCl_2 + H_2\\ n_M = n_{H_2} = \dfrac{2,24}{22,4} = 0,1(mol)\\ \Rightarrow M = \dfrac{5,6}{0,1} = 56(Fe)\\ \)

Vậy M là kim loại Fe

\(n_{FeCl_2} = n_{H_2} = 0,1(mol)\\ m_{FeCl_2} = 0,1.127 = 12,7(gam)\\ m_{dd\ sau\ pư} =m_{Fe} + m_{dd\ HCl} -m_{H_2} = 5,6 + 94,6 -0,1.2 = 100(gam)\\ C\%_{FeCl_2} = \dfrac{12,7}{100}.100\% = 12,7\%\)

\(n_{H_2}=\frac{5,6}{22,4}=0,25(mol)\\ m_{H_2}=0,25.2=0,5(g)\\ BT H:\\ n_{HCl}=2n_{H_2}=0,25.2=0,5(mol)\\ m_{HCl}=0,5.36,5=18,25(g)\\ BTKL:\\ m_{hh}+m_{HCl}=m_{muối}+m_{H_2}\\ 15+18,25=m_{muối}+0,5\\ \to m_{muối}=32,75(g)\\ \to D\)

a, Ta có: \(n_{Fe}=\dfrac{5,6}{56}=0,1\left(mol\right)\)

PT: \(Fe+2HCl\rightarrow FeCl_2+H_2\)

___0,1_________________0,1 (mol)

\(\Rightarrow V_{H_2}=0,1.22,4=2,24\left(l\right)\)

b, Ta có: \(n_{O_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)

PT: \(2H_2+O_2\underrightarrow{t^o}2H_2O\)

Xét tỉ lệ: \(\dfrac{0,1}{2}< \dfrac{0,3}{1}\), ta được O₂ dư.

Theo PT: \(n_{H_2O}=n_{H_2}=0,1\left(mol\right)\)

\(\Rightarrow m_{H_2O}=0,1.18=1,8\left(g\right)\)

Bạn tham khảo nhé!

n_Fe = 5.6/56 = 0.1 (mol) 

Fe + 2HCl => FeCl₂ + H₂

0.1...............................0.1

V_H2 = 0.1 * 22.4 = 2.24 (l) 

n_O2 = 6.72/22.4 = 0.3 (mol) 

2H₂ + O₂ -t⁰-> 2H₂O

0.1.....0.05.........0.1

=> O₂ dư 

m_H2O = 0.1 * 18 = 1.8 (g) 

Ta có: \(n_{Fe}=\dfrac{5,6}{56}=0,1\left(mol\right)\)

PT: \(Fe+2HCl\rightarrow FeCl_2+H_2\)

____0,1______0,2_____0,1____0,1 (mol)

a, \(C_{M_{HCl}}=\dfrac{0,2}{0,15}=\dfrac{4}{3}\left(M\right)\)

\(V_{H_2}=0,1.22,4=2,24\left(l\right)\)

b, \(FeCl_2+2NaOH\rightarrow2NaCl+Fe\left(OH\right)_2\)

Theo PT: \(n_{NaOH}=2n_{FeCl_2}=0,2\left(mol\right)\)

\(\Rightarrow V_{NaOH}=\dfrac{0,2}{2}=0,1\left(l\right)\)

\(1.\\ n_A=\dfrac{16,8}{A}mol\\ n_{H_2}=\dfrac{7,437}{24,79}=0,3mol\\ A+2HCl\rightarrow ACl_2+H_2\\ \Rightarrow\dfrac{16,8}{A}=0,3\\ \Rightarrow A=56g/mol\\ \Rightarrow A.là.Fe\\ \Rightarrow Chọn.A\\ 2.\\ n_{Fe}=\dfrac{5,6}{56}=0,1mol\\ Fe+2HCl\rightarrow FeCl_2+H_2\\ n_{Fe}=n_{H_2}=0,1mol\\ V_{H_2}=0,1.24,79=2,479l\\ \Rightarrow Chọn.B\\ 3.\\ Axit:H_2SO_4;HCl\\ \Rightarrow Chọn.B\\ 4.\\ 3,719l\Rightarrow3,7185\\ CTHH:R\\ n_R=\dfrac{3,6}{R}mol\\ n_{H_2}=\dfrac{3,7185}{24,79}=0,15mol\\ R+2HCl\rightarrow RCl_2+H_2\\ \Rightarrow\dfrac{3,6}{R}=0,15\\ \Rightarrow R=24g/mol,Mg\\ \Rightarrow Chọn.B\)

\(n_{Fe}=\dfrac{5.6}{56}=0.1\left(mol\right)\)

\(Fe+\dfrac{3}{2}Cl_2\underrightarrow{^{^{t^0}}}FeCl_3\)

\(0.1.......0.15..........0.1\)

\(V_{Cl_2}=0.15\cdot22.4=3.36\left(l\right)\)

\(m_{FeCl_3}=0.1\cdot162.5=16.25\left(g\right)\)

a.3.36l

b.13.25g