nFe=2,8/56=0,05(mol)

Fe+2HCl→FeCl2+H2

nHCl=2nFe=0,05.2=0,1(mol)

Vdd HCl=0,1/2=0,05(lít)

câu b đâu rồi bạn

\(n_{Fe}=\dfrac{2,8}{56}=0,05\left(mol\right)\)

PT :

\(Fe+2HCl\rightarrow FeCl_2+H_2\uparrow\)

0,05    0,1                       0,05 

\(a,V_{H_2}=0,05.22,4=1,12\left(l\right)\)

\(b,V_{HCl}=\dfrac{n}{C_M}=\dfrac{0,1}{2}=0,05\left(l\right)\)

\(a) n_{Zn} = \dfrac{19,5}{65} = 0,3(mol) ; n_{HCl} = 0,35.2 = 0,7(mol)\\ Zn + 2HCl \to ZnCl_2 + H_2\\ n_{HCl} = 0,7 > 2n_{Zn} = 0,6 \to HCl\ dư\\ n_{H_2} = n_{Zn} = 0,3(mol) \Rightarrow V_{H_2} = 0,3.22,4 = 6,72(lít)\\ b) m_{dd\ HCl} = 350.1,05 = 367,5(gam)\\ m_{dd\ sau\ pư} = 19,5 + 367,5 - 0,3.2 = 386,4(gam)\\ \Rightarrow C\%_{ZnCl_2} = \dfrac{0,3.136}{386,4}.100\% = 10,56\%\\ c) C\%_{HCl} = \dfrac{0,7.36,5}{367,5}.100\% = 6,95\%\)

a chưa tính C% của HCl dư rồi !

\(n_{Fe} = \dfrac{2,8}{56} = 0,05(mol)\\ Fe + 2HCl \to FeCl_2 + H_2\\ n_{HCl} =2n_{Fe} = 0,05.2 = 0,1(mol)\\ V_{dd\ HCl} = \dfrac{0,1}{2} = 0,05(lít)\)

PTHH: \(Fe+2HCl\rightarrow FeCl_2+H_2\uparrow\)

Ta có: \(n_{HCl}=2n_{Fe}=2\cdot\dfrac{2,8}{56}=0,1\left(mol\right)\)

\(\Rightarrow V_{HCl}=\dfrac{0,1}{2}=0,05\left(l\right)=50\left(ml\right)\)

a, \(n_{Mg}=\dfrac{2,4}{24}=0,1\left(mol\right)\)

PT: \(Mg+2HCl\rightarrow MgCl_2+H_2\)

Theo PT: \(n_{H_2}=n_{Mg}=0,1\left(mol\right)\Rightarrow V_{H_2}=0,1.22,4=2,24\left(l\right)\)

b, \(n_{HCl}=2n_{Mg}=0,2\left(mol\right)\Rightarrow V_{HCl}=\dfrac{0,2}{2}=0,1\left(l\right)\)

\(n_{Mg}=\dfrac{2,4}{24}=0,1\left(mol\right)\)

PTHH :

\(Mg+2HCl\rightarrow MgCl_2+H_2\uparrow\)

0,1        0,2                        0,1 

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

\(b,V=\dfrac{n}{C_M}=\dfrac{0,2}{2}=0,1\left(l\right)\)

\(a) Fe + 2HCl \to FeCl_2 + H_2\\ n_{FeCl_2} = n_{H_2} = n_{Fe} = \dfrac{5,6}{56} = 0,1(mol)\\ V_{H_2} = 0,1.22,4 = 2,24(lít)\\ b)m_{FeCl_2} = 0,1.127 = 12,7(gam)\\ c) n_{HCl} =2 n_{Fe} = 0,2(mol)\\ C_{M_{HCl}} = \dfrac{0,2}{0,2} = 1M\)

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

\(Fe+2HCl\rightarrow FeCl_2+H_2\)

\(0.1......0.2..........0.1..........0.1\)

\(V_{H_2}=0.1\cdot22.4=2.24\left(l\right)\)

\(m_{FeCl_2}=0.1\cdot127=12.7\left(g\right)\)

\(C_{M_{HCl}}=\dfrac{0.2}{0.2}=1\left(M\right)\)

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%

\(n_{Fe}=\dfrac{2,8}{56}=0,05\left(mol\right)\)

PTHH :

\(Fe+2HCl\rightarrow FeCl_2+H_2\)

0,05   0,1           0,05      0,05 

\(V_{H_2}=0,05.22,4=1,12\left(l\right)\)

\(V_{HCl}=\dfrac{n}{C_M}=\dfrac{0,1}{1}=0,1\left(l\right)\)

\(m_{FeCl_2}=0,05.127=6,35\left(g\right)\)