a/ \(n_{KOH}=0,2.1=0,2\left(mol\right);n_{H_2SO_4}=0,3.1=0,3\left(mol\right)\)

PTHH: 2KOH + H₂SO₄ → K₂SO₄ + 2H₂O

Mol:        0,2         0,1            0,1

Ta có: \(\dfrac{0,2}{2}< \dfrac{0,3}{1}\) ⇒ KOH hết, H₂SO₄ dư

b/ \(m_{H_2SO_4dư}=\left(0,3-0,1\right).98=19,6\left(g\right)\)

c/ V_{dd sau pứ} = 0,2 + 0,3 = 0,5 (l)

d/ \(C_{M_{ddK_2SO_4}}=\dfrac{0,1}{0,5}=0,2M\)

 \(C_{M_{ddH_2SO_4dư}}=\dfrac{0,3-0,1}{0,5}=0,4M\)

`n_[Fe]=[11,2]/56=0,2(mol)`

`n_[HCl]=0,3.2=0,6(mol)`

`Fe + 2HCl -> FeCl_2 + H_2 \uparrow`

`0,2`   `0,4`             `0,2`     `0,2`         `(mol)`

`a)` Ta có:`[0,2]/1 < [0,6]/2`

    `=>HCl` dư

`=>V_[H_2]=0,2.22,4=4,48(l)`

`b)HCl` còn dư sau p/ứ

`=>m_[HCl(dư)]=(0,6-0,4).36,5=7,3(g)`

`c)C_[M_[FeCl_2]]=[0,2]/[0,3]~~0,67(M)`

  `C_[M_[HCl(dư)]=[0,6-0,4]/[0,3]~~0,67(M)`

\(n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right)\)

\(n_{HCl}=0,3.2=0,6\left(mol\right)\)

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

0,2 <    0,6                        ( mol )

0,2       0,4          0,2        0,2      ( mol )

\(V_{H_2}=0,2.22,4=4,48\left(l\right)\)

Chất dư là HCl

\(m_{HCl\left(dư\right)}=\left(0,6-0,4\right).36,5=7,3\left(g\right)\)

\(C_{M_{FeCl_2}}=\dfrac{0,2}{0,3}=0,66\left(M\right)\)

\(C_{M_{HCl\left(dư\right)}}=\dfrac{0,2}{0,3}=0,66\left(M\right)\)

Ta có: 0,11>0,12, ta được Fe dư.

a, Theo PT: 

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

Ta có: \(\left\{{}\begin{matrix}n_{Fe}=\dfrac{5,6}{56}=0,1\left(mol\right)\\n_{HCl}=0,1\cdot1=0,1\left(mol\right)\end{matrix}\right.\)

Xét tỉ lệ: \(\dfrac{0,1}{1}>\dfrac{0,1}{2}\) \(\Rightarrow\) Sắt còn dư, HCl p/ứ hết

\(\Rightarrow n_{Fe\left(dư\right)}=0,05\left(mol\right)=n_{FeCl_2}\) \(\Rightarrow\left\{{}\begin{matrix}m_{Fe\left(dư\right)}=0,05\cdot56=2,8\left(g\right)\\C_{M_{FeCl_2}}=\dfrac{0,05}{0,1}=0,5\left(M\right)\end{matrix}\right.\)

\(a/ \\ Fe+2HCl \rightarrow FeCl_2+H_2\\ n_{Fe}=\frac{5,6}{56}=0,1(mol)\\ n_{HCl}=0,1.1=0,1(mol)\\ Fe: 0,1>HCl: \frac{0,1}{2}=0,05\\ \Rightarrow \text{Fe dư, HCl hết} n_{H_2}=\frac{1}{2}.n_{HCl}=0,05(mol)\\ V_{H_2}=1,12l\\ b/ \\ \text{Fe dư}\\ n_{Fe}=\frac{1}{2}.n_{HCl}=0,05(mol)\\ m_{Fe}=(0,1-0,05).56=2,8g\\ C/ \\ n_{FeCl_2}=\frac{1}{2}.n_{HCl}=0,05(mol)\\ CM_{FeCl_2}=0,5M \)

Đề cho lượng 1 chất sao lại hỏi dư hay k

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

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

\(n_{HCL}=0,1.1=0,1\left(mol\right)\)

\(\Rightarrow n_{H_2}=2nH_2=2,0,1=0,2\left(mol\right)\)

\(\Rightarrow V_{H_2}=0,2.22,4=4,48\left(ml\right)\)

b) sau pư Fe dư

ta có 1 molFe Pư 2 molHCL

  0,05 molFe pư 0,1 HCL

\(\Rightarrow n_{Fe\left(dư\right)}:0,1-0,05=0,05\left(mol\right)\)

c)\(C_{MFeCL_2}=\dfrac{2.n_{HCL}}{0,1}=2M\)

PT: \(Zn+H_2SO_4\rightarrow ZnSO_4+H_2\)

a, Ta có: \(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\)

\(n_{H_2SO_4}=0,2.1=0,2\left(mol\right)\)

Xét tỉ lệ: \(\dfrac{0,1}{1}< \dfrac{0,2}{1}\). ta được H₂SO₄ dư.

Theo PT: \(n_{H_2SO_4\left(pư\right)}=n_{ZnSO_4}=n_{Zn}=0,1\left(mol\right)\)

\(\Rightarrow n_{H_2SO_4\left(dư\right)}=0,2-0,1=0,1\left(mol\right)\)

b, Ta có: \(m_{ZnSO_4}=0,1.161=16,1\left(g\right)\)

c, \(C_{M_{H_2SO_4\left(dư\right)}}=\dfrac{0,1}{0,2}=0,5M\)

\(C_{M_{ZnSO_4}}=\dfrac{0,1}{0,2}=0,5M\)

Bạn tham khảo nhé!

\(n_{Fe}=\dfrac{11,2}{56}=0,2mol\)

\(n_{HCl}=2,5.0,2=0,5mol\)

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

0,2  <  0,5                            ( mol )

0,2      0,4            0,2         0,2     ( mol )

Chất dư là HCl

\(m_{HCl\left(dư\right)}=\left(0,5-0,4\right).36,5=3,65g\)

\(V_{H_2}=0,2.22,4=4,48l\)

\(C_{M_{FeCl_2}}=\dfrac{0,2}{0,2}=1M\)

\(n_{Zn}=\dfrac{13}{65}=0.2\left(mol\right)\)

\(n_{HCl}=\dfrac{182.5\cdot10}{100\cdot36.5}=0.5\left(mol\right)\)

\(Zn+2HCl\rightarrow ZnCl_2+H_2\)

\(0.2......0.4..........0.2........0.2\)

\(n_{HCl\left(dư\right)}=0.5-0.4=0.1\left(mol\right)\)

\(m_{HCl\left(dư\right)}=0.1\cdot36.5=3.65\left(g\right)\)

\(V_{H_2}=0.2\cdot22.4=4.48\left(l\right)\)

\(m_{\text{dung dịch sau phản ứng}}=13+182.5-0.2\cdot2=195.1\left(g\right)\)

\(C\%_{HCl\left(dư\right)}=\dfrac{3.65}{195.1}\cdot100\%=1.87\%\)

\(C\%_{ZnCl_2}=\dfrac{0.2\cdot136}{195.1}\cdot100\%=13.94\%\)

\(Fe+H_2SO_4\rightarrow FeSO_4+H_2\\ n_{Fe}=\dfrac{28}{56}=0,5\left(mol\right);n_{H_2SO_4}=0,05.2=0,1\left(mol\right)\\ Vì:\dfrac{0,5}{1}>\dfrac{0,1}{1}\Rightarrow Fe.dư\\ n_{Fe\left(p.ứ\right)}=n_{FeSO_4}=n_{H_2}=n_{H_2SO_4}=0,1\left(mol\right)\\ m_{Fe\left(p.ứ\right)}=0,1.56=5,6\left(g\right);m_{H_2}=2.0,1=0,2\left(g\right)\\ m_{FeSO_4}=152.0,1=15,2\left(g\right);m_{H_2SO_4}=98.0,1=9,8\left(g\right)\)