\(n_{Na}=\dfrac{2,3}{23}=0,1\left(mol\right)\)

PTHH: 2Na + 2H₂O --> 2NaOH + H₂

            0,1-------------->0,1---->0,05

=> V_H2 = 0,05.22,4 = 1,12 (l)

m_{dd sau pư} = 2,3 + 197,8 - 0,05.2 = 200 (g)

=> \(C\%=\dfrac{0,1.40}{200}.100\%=2\%\)

\(V_{dd}=\dfrac{200}{1,08}=\dfrac{5000}{27}\left(ml\right)=\dfrac{5}{27}\left(l\right)\)

=> \(C_M=\dfrac{0,1}{\dfrac{5}{27}}=0,54M\)

Pt: \(2CH_3COOH+Zn\rightarrow\left(CH_3COO\right)_2Zn+H_2\)

\(n_{\left(CH_3COO\right)_2Zn}=\dfrac{14,2}{183}\approx0.077mol\)

Theo pt: nH₂ = n(CH₃COO)₂Zn = 0,077mol

=> VH₂ = 1,7248l

b) Theo pt: nCH₃COOH = 2n(CH₃COO)₂Zn = 0,154 mol

=> CM_CH3COOH = 0,154 : 0,25 = 0,616M

`a)PTHH:`

  `Zn + 2HCl -> ZnCl_2 + H_2`

`0,02`                       `0,02`    `0,02`        `(mol)`

`n_[Zn]=[1,3]/65=0,02(mol)`

`b)V_[H_2]=0,02.22,4=0,448(l)`

`c)C%_[ZnCl_2]=[0,02.136]/[1,3+50-0,02.2].100~~5,31%`

\(n_{Zn}=\dfrac{1,3}{65}=0,02\left(mol\right)\)

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

0,02   0,04         0,02       0,02  ( mol )

\(V_{H_2}=0,02.22,4=0,448\left(l\right)\)

\(C\%_{ZnCl_2}=\dfrac{0,02.136}{1,3+50-0,02.2}.100=5,3\%\)

\(n_{Zn}=\dfrac{1,3}{65}=0,02\left(mol\right)\\ pthh:Zn+2HCl\rightarrow ZnCl_2+H_2\uparrow\) 
         0,02                 0,02           0,02 
\(V_{H_2}=0,02.22,4=0,448\left(l\right)\\ m_{\text{dd}}=1,3+50-\left(0,02.2\right)=51,26\left(g\right)\\ C\%_{ZnCl_2}=\dfrac{0,02.136}{51,26}.100\%=5,3\%\)

Ta có: \(n_{Na}=\dfrac{9,2}{23}=0,4\left(mol\right)\)

\(PTHH:2Na+2H_2O--->2NaOH+H_2\uparrow\)

a. Theo PT: \(n_{H_2}=\dfrac{1}{2}.n_{Na}=\dfrac{1}{2}.0,4=0,2\left(mol\right)\)

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

b. Theo PT: \(n_{NaOH}=n_{Na}=0,4\left(mol\right)\)

\(\Rightarrow m_{NaOH}=0,4.40=16\left(g\right)\)

Ta có: \(m_{dd_{NaOH}}=9,2+200-0,2.2=208,8\left(g\right)\)

\(\Rightarrow C_{\%_{NaOH}}=\dfrac{16}{208,8}.100\%=7,66\%\)

Fe không có tác dụng nước ở đk thường được em? Lớp 8 thầy cô ra đề ri là bất ổn rầu

n Zn= 19,5/65=0,3 (mol).

PTPƯ: Zn(0.3) +   HCl(0.6) ---->  ZnCl2(0.3) + H2(0,3)

mHCl=0,6.36.5=21.9(g)

a) C%HCl= 21.9/300.100%=7,3%

b) VH2=0,3.22,4=6,72(lít)

c) mH2=0,3.2=0,6(g)

mZnCl2=0,3.136=40,8(g)

mddZnCl2 =(19,5+300)-0,6=318,9(g)

C%=mZnCl2/mddZnCl2.100= 40,8/318,9.100=12,793%

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

   \(m_{H_2SO_4}=147.10\%=14,7\left(g\right)\Rightarrow n_{H_2SO_4}=\dfrac{14,7}{98}=0,15\left(mol\right)\)

PTHH: Zn + H₂SO₄ → ZnSO₄ + H₂

Mol:     0,1       0,1            0,1       0,1

Ta có: \(\dfrac{0,1}{1}< \dfrac{0,15}{1}\) ⇒ Zn hết, H₂SO₄ dư

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

c) m_{dd sau pứ} = 6,5 + 147 - 0,1.2 = 153,3 (g)

\(C\%_{ddZnSO_4}=\dfrac{0,1.161.100\%}{153,3}=10,502\%\)

\(C\%_{ddH_2SO_4dư}=\dfrac{\left(0,15-0,1\right).98.100\%}{153,3}=3,196\%\) 

\(n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right)\\a, PTHH:Fe+H_2SO_4\rightarrow FeSO_4+H_2\\ b,n_{H_2}=n_{H_2SO_4}=n_{Fe}=0,2\left(mol\right)\\ V_{H_2\left(đkc\right)}=0,2.24,79=4,958\left(l\right)\\ c,C_{MddH_2SO_4}=\dfrac{0,2}{0,4}=0,5\left(M\right)\)