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

Ta có: \(n_{H_2}=\dfrac{7,84}{22,4}=0,35\left(mol\right)\)

Theo PT: \(n_{Zn}=n_{H_2}=0,35\left(mol\right)\)

\(\Rightarrow m_{Zn}=0,35.65=22,75\left(g\right)\)

b, Theo PT: \(n_{HCl\left(pư\right)}=2n_{H_2}=0,7\left(mol\right)\)

Mà: axit dùng dư 10% so với lượng pư.

\(\Rightarrow n_{HCl}=0,7+0,7.10\%=0,77\left(mol\right)\)

\(\Rightarrow V_{ddHCl}=\dfrac{0,77}{2,8}=0,275\left(l\right)\)

c, Ta có: \(D=\dfrac{m}{V}\Rightarrow m_{ddHCl}=0,275.1000.1,04=286\left(g\right)\)

d, Theo PT: \(n_{ZnCl_2}=n_{H_2}=0,35\left(mol\right)\)

Dd X gồm: ZnCl₂ và HCl dư.

n_HCl dư = 07.10% = 0,07 (mol)

Ta có: m _{dd sau pư} = m_Zn + m _{dd HCl} - m_H2 = 308,05 (g)

\(\Rightarrow\left\{{}\begin{matrix}C\%_{ZnCl_2}=\dfrac{0,35.136}{308,05}.100\%\approx15,452\%\\C\%_{HCl\left(dư\right)}=\dfrac{0,07.36,5}{308,05}.100\%\approx0,829\%\end{matrix}\right.\)

a, \(Zn+2HCl\rightarrow ZnCl_2+H_2\)

b, \(n_{H_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)

Theo PT: \(n_{Zn}=n_{H_2}=0,3\left(mol\right)\)

\(\Rightarrow m_{Zn}=0,3.65=19,5\left(g\right)\)

c, \(n_{HCl}=2n_{H_2}=0,6\left(mol\right)\)

\(\Rightarrow C_{M_{HCl}}=\dfrac{0,6}{0,1}=6\left(M\right)\)

a) $Zn + 2HCl \to ZnCl_2 + H_2$

b) n Zn = n H2 = 4,48/22,4 = 0,2(mol)

m Zn = 0,2.65 = 13(gam)

c) n HCl = 2n H2 = 0,4(mol)

=> C% HCl = 0,4.36,5/200 .100% = 7,3%

\(n_{Zn}=\dfrac{26}{65}=0,4\left(mol\right)\\ pthh:Zn+2HCl\rightarrow ZnCl_2+H_2\uparrow\) 
           0,4       0,8        0,4           0,4
\(a,V_{H_2}=0,4.22,4=8,96\left(l\right)\\ b,C\%_{HCl}=\dfrac{0,8.36,5}{150}.100\%=19,5\%\\ c,m_{\text{dd}}=26+150-\left(0,4.2\right)=175,2\left(g\right)\\ C\%_{ZnCl_2}=\dfrac{0,4.136}{175,2}.100\%=31\%\)

a, \(Zn+2HCl\rightarrow ZnCl_2+H_2\)

b, \(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\)

Theo PT: \(n_{H_2}=n_{Zn}=0,2\left(mol\right)\Rightarrow V_{H_2}=0,2.22,4=4,48\left(l\right)\)

c, \(n_{ZnCl_2}=n_{Zn}=0,2\left(mol\right)\Rightarrow m_{ZnCl_2}=0,2.136=27,2\left(g\right)\)

d, \(n_{HCl}=2n_{Zn}=0,4\left(mol\right)\Rightarrow m_{HCl}=0,4.36,5=14,6\left(g\right)\)

\(\Rightarrow m_{ddHCl}=\dfrac{14,6}{7,3\%}=200\left(g\right)\)

⇒ m _{dd sau pư} = 13 + 200 - 0,2.2 = 212,6 (g)

\(\Rightarrow C\%_{ZnCl_2}=\dfrac{27,2}{212,6}.100\%\approx12,79\%\)

a)

$Fe + 2HCl \to FeCl_2 + H_2$

b) Theo PTHH : $n_{Fe} = n_{H_2} = \dfrac{3,36}{22,4} = 0,15(mol)$
$m_{Fe} = 0,15.56 = 8,4(gam)$

c) $n_{HCl} = 2n_{H_2} = 0,3(mol)$
$\Rightarrow C_{M_{HCl}} = \dfrac{0,3}{0,05} = 6M$

d) $2NaOH + H_2SO_4 \to Na_2SO_4 + 2H_2O$

$n_{H_2SO_4} = \dfrac{1}{2}n_{NaOH} = 0,25(mol)$

$m_{dd\ H_2SO_4} = \dfrac{0,25.98}{20\%} = 122,5(gam)$

$V_{dd\ H_2SO_4} = \dfrac{122,5}{1,14} = 107,5(ml)$

\(n_{H2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)

a) Pt : \(Fe+2HCl\rightarrow FeCl_2+H_2|\)

            1         2             1          1

          0,15     0,3                      0,15

b) \(n_{Fe}=\dfrac{0,15.1}{1}=0,15\left(mol\right)\)

⇒ \(m_{Fe}=0,15.56=8,4\left(g\right)\)

c) \(n_{HCl}=\dfrac{0,15.2}{1}=0,3\left(mol\right)\)

50ml = 0,05l

\(C_{M_{ddHCl}}=\dfrac{0,3}{0,05}=6\left(M\right)\)

 Chúc bạn học tốt

Câu 1:

a. PTHH: MgCl₂ + HCl ---x--->

CaCO₃ + 2HCl ---> CO₂↑ + H₂O + CaCl₂ (1)

b. Ta có: \(n_{CO_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)

Theo PT₍₁₎: \(n_{HCl}=2.n_{CO_2}=2.0,3=0,6\left(mol\right)\)

Đổi 400ml = 0,4 lít

=> \(C_{M_{HCl}}=\dfrac{0,6}{0,4}=1,5M\)

c. PTHH: HCl + NaOH ---> NaCl + H₂O (2)

Vậy chất tác dụng với nước bắp cải tím là NaCl (muối ăn.)

Vậy dung dịch sau phản ứng làm nước bắp cải tím thành màu xam lam đậm.

Câu 2:

a. PTHH: CuO + H₂SO₄ ---> CuSO₄ + H₂O

b. Ta có: \(n_{CuO}=\dfrac{8}{80}=0,1\left(mol\right)\)

Ta lại có: \(C_{\%_{H_2SO_4}}=\dfrac{m_{H_2SO_4}}{100}.100\%=19,6\%\)

=> \(m_{H_2SO_4}=19,6\left(g\right)\)

=> \(n_{H_2SO_4}=\dfrac{19,6}{98}=0,2\left(mol\right)\)

Ta thấy: \(\dfrac{0,1}{1}< \dfrac{0,2}{1}\)

Vậy H₂SO₄ dư.

Theo PT: \(n_{CuSO_4}=n_{CuO}=0,1\left(mol\right)\)

=> \(m_{CuSO_4}=0,1.160=16\left(g\right)\)

Ta có: \(m_{dd_{CuSO_4}}=8+100=108\left(g\right)\)

=> \(C_{\%_{CuSO_4}}=\dfrac{16}{108}.100\%=14,81\%\)

chỗ câu 1/c phải tính số mol HCl và NaOH thì -> số mol NaOH dư khi đấy cho giấy quỳ tím vào thì hóa xanh chứ nhỉ?

\(a,PTHH:Zn+2HCl\rightarrow ZnCl_2+H_2\\ b,n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\\ n_{HCl}=2\cdot0,15=0,3\left(mol\right)\)

Vì \(\dfrac{n_{Zn}}{1}>\dfrac{n_{HCl}}{2}\) nên sau p/ứ Zn dư

\(\Rightarrow n_{Zn}=\dfrac{1}{2}n_{HCl}=0,15\left(mol\right)\\ \Rightarrow m_{Zn}=0,15\cdot65=9,75\\ \Rightarrow m_{Zn\left(dư\right)}=13-9,75=3,25\left(g\right)\\ c,n_{H_2}=n_{Zn}=0,15\left(mol\right)\\ \Rightarrow V_{H_2}=0,15\cdot22,4=3,36\left(l\right)\)