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

PTHH: Fe + 2HCl --> FeCl₂ + H₂

         0,1---------------------->0,1

=> V_H2 =0,1.22,4 = 2,24(l)

\(PTHH:Fe+2HCl\rightarrow FeCl_2+H_2\\ n_{Fe}=\dfrac{m}{M}=\dfrac{5,6}{56}=0,1\left(mol\right)\\ Theo.PTHH:n_{H_2}=n_{Fe}=0,1\left(mol\right)\\ V_{H_2\left(đktc\right)}=n.22,4=0,1.22,4=2,24\left(l\right)\)

\(a.n_{Fe}=\dfrac{5,6}{56}=0,1\left(mol\right)\\ PTHH:Fe+2HCl\xrightarrow[]{}FeCl_2+H_2\)

tỉ lệ        :1        2            1            1

số mol   :0,1     0,2         0,1          0,1

\(V_{H_2}=0,1.22,4=2,24\left(l\right)\\ b)m_{HCl}=0,2.36,5=7,3\left(g\right)\\ C_{\%HCl}=\dfrac{7,3}{500}\cdot100\%=1,46\%\)

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)

Fe + 2HCl -> FeCl2 + H2
nFe = 5,6/56 = 0,1 mol
=>nH2 = 0,1 mol
=> VH2= 0,1*22,4= 2,24 lít

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

PTHH: Fe + 2HCl ---> FeCl₂ + H₂

          0,1-->0,2------------------>0,1

=> \(\left\{{}\begin{matrix}m_{ddHCl}=\dfrac{0,2.36,5}{15\%}=\dfrac{146}{3}\left(g\right)\\V_{H_2}=0,1.22,4=4,48\left(l\right)\end{matrix}\right.\)

a, \(n_{Al}=\dfrac{2,7}{27}=0,1\left(mol\right)\)

PT: \(2Al+6HCl\rightarrow2AlCl_3+3H_2\)

Theo PT: \(n_{H_2}=\dfrac{3}{2}n_{Al}=0,15\left(mol\right)\Rightarrow V_{H_2}=0,15.22,4=3,36\left(l\right)\)

b, Có lẽ đề hỏi bao nhiêu gam đồng thay vì "bao nhiêu gam sắt" bạn nhỉ?

\(n_{CuO}=\dfrac{20}{80}=0,25\left(mol\right)\)

PT: \(CuO+H_2\underrightarrow{t^o}Cu+H_2O\)

Xét tỉ lệ: \(\dfrac{0,25}{1}>\dfrac{0,15}{1}\), ta được CuO dư.

Theo PT: \(n_{Cu}=n_{H_2}=0,15\left(mol\right)\Rightarrow m_{Cu}=0,15.64=9,6\left(g\right)\)

Đáp án C

F e   +   2 H C l   →   F e C l 2   +   H 2     N h ì n   v à o   p h ư ơ n g   t r ì n h   t h ấ y   n F e   =   n H 2   =   5 , 6 / 56   =   0 , 1   m o l     V H 2   =   0 , 1 . 22 , 4   =   2 , 24   l   =   2240   m l

a)

$Mg + 2HCl \to MgCl_2 + H_2$

Theo PTHH : 

$n_{MgCl_2} = n_{H_2} = \dfrac{5,6}{22,4} = 0,25(mol)$
$m_{MgCl_2} = 0,25.95 = 23,75(gam)$

b)

$n_{HCl} = 2n_{H_2} = 0,5(mol)$
$m_{dd\ HCl} = \dfrac{0,5.36,5}{7,3\%} = 250(gam)$

c)

$2K + 2H_2O \to 2KOH + H_2$
$n_K = 2n_{H_2} = 0,5(mol)$
$m_K = 0,5.39 = 19,5(gam)$

a) PTHH: \(Zn+2HCl\rightarrow ZnCl_2+H_2\)

b) \(n_{ZnCl_2}=\dfrac{20,4}{136}=0,15\left(mol\right)\)

\(n_{H_2}=n_{ZnCl_2}=0,15\left(mol\right)\)

\(V_{H_2\left(đktc\right)}=0,15.22,4=3,36\left(l\right)\)

c) \(m_{H_2}=0,15.2=0,3\left(g\right)\)

\(n_{HCl}=2n_{H_2}=0,3\left(mol\right)\)

\(m_{HCl}=0,3.36,5=10,95\left(g\right)\)

\(m_{Zn}=20,4+0,3-10,95=9,75\left(g\right)\)

\(n_{Al}=\dfrac{5,4}{27}=0,2mol\)

\(2Al+6HCl\rightarrow2AlCl_3+3H_2\)

0,2       0,6          0,2          0,3

a)\(V_{H_2}=0,3\cdot22,4=6,72l\)

b)\(C_{M_{HCl}}=\dfrac{0,6}{0,15}=4M\)

d)\(n_{PbO}=\dfrac{66,9}{207+16}=0,3mol\)

   \(PbO+H_2\rightarrow Pb+H_2O\)

   0,3       0,3      0,3

   \(m_{kl}=m_{Pb}=0,3\cdot207=62,1g\)