Ta có: \(n_{HCl}=0,2.1=0,2\left(mol\right)\)

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

PT: \(HCl+NaOH\rightarrow NaCl+H_2O\)

Xét tỉ lệ: \(\dfrac{0,2}{1}< \dfrac{0,6}{1}\), ta được NaOH dư.

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

\(\Rightarrow n_{NaOH\left(dư\right)}=0,6-0,2=0,4\left(mol\right)\)

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

- Quỳ tím hóa xanh do NaOH dư.

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

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

b, Ta có: 27n_Al + 56n_Fe = 5,5 (1)

Theo PT: \(n_{H_2}=\dfrac{3}{2}n_{Al}+n_{Fe}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\left(2\right)\)

Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}n_{Al}=0,1\left(mol\right)\\n_{Fe}=0,05\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}\%m_{Al}=\dfrac{0,1.27}{5,5}.100\%\approx49,09\%\\\%m_{Fe}\approx50,91\%\end{matrix}\right.\)

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

Ta có: \(n_{Fe}=\dfrac{0,56}{56}=0,01\left(mol\right)\)

Theo PT: \(n_{H_2SO_4}=n_{FeSO_4}=n_{H_2}=n_{Fe}=0,01\left(mol\right)\)

b, \(m_{FeSO_4}=0,01.152=1,52\left(g\right)\)

\(V_{H_2}=0,01.22,4=0,224\left(l\right)\)

c, \(m_{ddH_2SO_4}=\dfrac{0,01.98}{19,6\%}=5\left(g\right)\)

a, \(2Al+3CuSO_4\rightarrow Al_2\left(SO_4\right)_3+3Cu\)

b, Ta có: \(n_{Al}=\dfrac{2,7}{27}=0,1\left(mol\right)\)

\(m_{ddCuSO_4}=120.1,12=134,4\left(g\right)\)

\(\Rightarrow n_{CuSO_4}=\dfrac{134,4.10\%}{160}=0,084\left(mol\right)\)

Xét tỉ lệ: \(\dfrac{0,1}{2}>\dfrac{0,084}{3}\), ta được Al dư.

Theo PT: \(\left\{{}\begin{matrix}n_{Cu}=n_{CuSO_4}=0,084\left(mol\right)\\n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{3}n_{CuSO_4}=0,028\left(mol\right)\end{matrix}\right.\)

n_{Al (pư)} = 2/3n_CuSO4 = 0,056 (mol)

Ta có: m _{dd sau pư} = 0,056.27 + 134,4 - 0,084.64 = 130,536 (g)

\(\Rightarrow C\%_{Al_2\left(SO_4\right)_3}=\dfrac{0,028.342}{130,536}.100\%\approx7,34\%\)

\(Fe\left(OH\right)_n+nHCl\rightarrow FeCl_n+nH_2O\)

Ta có: \(n_{Fe\left(OH\right)_n}=\dfrac{10,7}{56+17n}\left(mol\right)\)

\(n_{FeCl_n}=\dfrac{16,25}{56+35,5n}\left(mol\right)\)

Theo PT: \(n_{Fe\left(OH\right)_n}=n_{FeCl_n}\)

\(\Rightarrow\dfrac{10,7}{56+17n}=\dfrac{16,25}{56+35,5n}\)

\(\Rightarrow n=3\)

Vậy: CTHH cần tìm là Fe(OH)₃

a, Ta có: 24n_Mg + 56n_Fe = 12,8 (1)

PT: \(Mg+2HCl\rightarrow MgCl_2+H_2\)

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

Theo PT: \(n_{H_2}=n_{Mg}+n_{Fe}=\dfrac{8,96}{22,4}=0,4\left(mol\right)\left(2\right)\)

Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}n_{Mg}=0,3\left(mol\right)\\n_{Fe}=0,1\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}m_{Mg}=0,3.24=7,2\left(g\right)\\m_{Fe}=0,1.56=5,6\left(g\right)\end{matrix}\right.\)

b, \(n_{HCl}=2n_{H_2}=0,8\left(mol\right)\)

\(\Rightarrow V_{HCl}=\dfrac{0,8}{2}=0,4\left(l\right)\)

c, \(MgCl_2+2NaOH\rightarrow Mg\left(OH\right)_2+2NaCl\)

\(FeCl_2+2NaOH\rightarrow Fe\left(OH\right)_2+2NaCl\)

Theo PT: \(\left\{{}\begin{matrix}n_{Mg\left(OH\right)_2}=n_{MgCl_2}=n_{Mg}=0,3\left(mol\right)\\n_{Fe\left(OH\right)_2}=n_{FeCl_2}=n_{Fe}=0,1\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow m_{\downarrow}=0,3.58+0,1.90=26,4\left(g\right)\)

Bạn đăng câu hỏi đúng môn nhé.

a, \(HCl+NaOH\rightarrow NaCl+H_2O\)

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

Theo PT: \(n_{NaOH}=n_{NaCl}=n_{HCl}=0,6\left(mol\right)\)

\(\Rightarrow m_{NaOH}=0,6.40=24\left(g\right)\)

\(\Rightarrow m_{ddNaOH}=\dfrac{24}{20\%}=120\left(g\right)\)

c, \(m_{NaCl}=0,6.58,5=35,1\left(g\right)\)

Ta có: \(n_{HCl}=\dfrac{182,5.10\%}{36,5}=0,5\left(mol\right)\)

PT: \(A+2HCl\rightarrow ACl_2+H_2\)

Theo PT: \(n_A=\dfrac{1}{2}n_{HCl}=0,25\left(mol\right)\)

\(\Rightarrow M_A=\dfrac{6}{0,25}=24\left(g/mol\right)\)

→ A là Mg.

Ta có: \(n_{Mg}=\dfrac{2,4}{24}=0,1\left(mol\right)\)

PT: \(Mg+2HCl\rightarrow MgCl_2+H_2\)

Theo PT: \(n_{MgCl_2}=n_{H_2}=n_{Mg}=0,1\left(mol\right)\)

a, \(m_{MgCl_2}=0,1.95=9,5\left(g\right)\)

b, \(V_{H_2}=0,1.24,79=2,479\left(l\right)\)

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

\(\Rightarrow m_{ddHCl}=\dfrac{0,2.36,5}{3,65\%}=200\left(g\right)\)