\(n_{H_2}=\dfrac{0,224}{22,4}=0,01\left(mol\right)\\ Fe+2HCl\rightarrow FeCl_2+H_2\\ n_{Fe}=n_{H_2}=0,01\left(mol\right)\\ \Rightarrow a=m_{Fe}=0,01.56=0,56\left(g\right)\\ \Rightarrow C\)

d

Chọn B

\(a)\\ Fe + 2HCl \to FeCl_2 + H_2\)

b)

\(n_{Fe} = \dfrac{22,4}{56}= 0,4(mol)\\ n_{H_2} = \dfrac{6,72}{22,4} = 0,3(mol)\)

Ta thấy : \(n_{Fe} > n_{H_2}\) nên Fe dư.

Theo PTHH :

\(n_{Fe\ pư} = n_{H_2} = 0,3(mol)\\ \Rightarrow m_{Fe\ pư} = 0,3.56 = 16,8(gam)\)

c)

Ta có : 

\(n_{FeCl_2} = n_{H_2} = 0,3(mol)\\ \Rightarrow m_{FeCl_2} = 0,3.127 = 38,1(gam)\)

\(n_{Al}=\dfrac{13,5}{27}=0,5mol\)

\(n_{H_2SO_4}=\dfrac{98}{98}=1mol\)

\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)

0,5         1                    0              0

0,5         0,75               0,25        0,75

0            0,25               0,25        0,75

\(V_{H_2}=0,75\cdot22,4=16,8l\)

Chọn B

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

$n_{Al} = \dfrac{8,1}{27} = 0,3(mol)$
$2Al + 3H_2SO_4 \to Al_2(SO_4)_3 + 3H_2$
$FeO + H_2SO_4 \to FeSO_4 + H_2O$
$n_{H_2} = \dfrac{3}{2}n_{Al} = 0,45(mol)$

$V = 0,45.22,4 = 10,08(lít)$

\(n_{Al}=\frac{8,1}{27}=0,3mol\\ 2Al+3H_2SO_4\rightarrow Al_2(SO_4)_3 +3H_2 n_{H_2}=0,45mol\\ V=10,08l\)

a) Fe + H₂SO₄ --> FeSO₄ + H₂

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

PTHH: Fe + H₂SO₄ --> FeSO₄ + H₂

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

=> V_H2 = 0,1.22,4 = 2,24 (l)

c) \(n_{CuO}=\dfrac{12}{80}=0,15\left(mol\right)\)

PTHH: CuO + H₂ --t^o--> Cu + H₂O

Xét tỉ lệ: \(\dfrac{0,15}{1}>\dfrac{0,1}{1}\) => CuO dư, H₂ hết

PTHH: CuO + H₂ --t^o--> Cu + H₂O

              0,1<--0,1------->0,1

=> m_CuO(dư) = (0,15 - 0,1).80 = 4 (g)

m_Cu = 0,1.64 = 6,4 (g)

a, PT: \(Fe+H_2SO_4\rightarrow H_2SO_4+H_2\)

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

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

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

c, Ta có: \(n_{CuO}=\dfrac{12}{80}=0,15\left(mol\right)\)

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

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

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

\(\Rightarrow n_{CuO\left(dư\right)}=0,05\left(mol\right)\Rightarrow m_{CuO\left(dư\right)}=0,05.80=4\left(g\right)\)

\(m_{Cu}=0,1.64=6,4\left(g\right)\)

Bạn tham khảo nhé!

a)

$Fe + 2HCl \to FeCl_2 + H_2$

Theo PTHH : 

$n_{Fe} = n_{H_2} = \dfrac{11,2}{22,4} = 0,5(mol)$
$A = 0,5.56 = 28(gam)$

b) $n_{HCl} = 2n_{H_2} = 1(mol)$
$m_{HCl} = 1.36,5 = 36,5(gam)$

c) $m_{dd\ HCl} = 36,5 : 20\% = 182,5(gam)$

$m_{dd\ sau\ pư} = 28 + 182,5 - 0,5.2 = 209,5(gam)$

$C\%_{FeCl_2} = \dfrac{0,5.127}{209,5}.100\% = 30,3\%$

Bài 1.

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

\(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)

0,1         0,1         0,1          0,1

\(V_{H_2}=0,1\cdot22,4=2,24l\)

\(n_{CuO}=\dfrac{12}{80}=0,15mol\)

\(CuO+H_2\rightarrow Cu+H_2O\)

0,15      0,1

\(\Rightarrow CuO\) dư và dư \(\left(0,15-0,1\right)\cdot80=4g\)

Bài 2.

\(n_P=\dfrac{3,1}{31}=0,1mol\)

\(4P+5O_2\underrightarrow{t^o}2P_2O_5\)

0,1     0,125

\(V_{O_2}=0,125\cdot22,4=2,8l\)

\(n_{Zn}=\dfrac{19,5}{65}=0,3mol\)

\(2Zn+O_2\underrightarrow{t^o}2ZnO\)

0,3       0,125  0

0,25     0,125  0,25

0,05       0       0,25

\(\Rightarrow ZnO\) dư và dư \(0,05\cdot81=4,05g\)

Bài 1.

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

PTHH: Fe + H₂SO₄ ---> FeSO₄ + H₂

Mol:     0,1                                    0,1

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

c, \(n_{CuO}=\dfrac{12}{80}=0,15\left(mol\right)\)

Ta có: \(\dfrac{0,15}{1}>\dfrac{0,1}{1}\) ⇒ CuO dư, H₂ hết

PTHH: CuO + H₂ ---t^o----> Cu + H₂O

Mol:      0,1     0,1

\(m_{CuOdư}=\left(0,15-0,1\right).80=4\left(g\right)\)