\(n_{CO_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)

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

\(\Rightarrow\dfrac{n_{NaOH}}{n_{CO_2}}=\dfrac{0,1}{0,15}=\dfrac{2}{3}\)

→ Pư tạo NaHCO₃ và CO₂ dư.

PT: \(CO_2+NaOH\rightarrow NaHCO_3\)

_____________0,1________0,1 (mol)

\(\Rightarrow C_{M_{NaHCO_3}}=\dfrac{0,1}{0,1}=1\left(M\right)\)

Ta có: \(n_{CO_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)

\(n_{NaOH}=0,15.3=0,45\left(mol\right)\)

\(\Rightarrow\dfrac{n_{NaOH}}{n_{CO_2}}=\dfrac{0,45}{0,15}=3\)

→ Pư tạo Na₂CO₃ và NaOH dư.

PT: \(CO_2+2NaOH\rightarrow Na_2CO_3+H_2O\)

______0,15_____0,3_______0,15 (mol)

n_{NaOH (dư)} = 0,45 - 0,3 = 0,15 (mol)

\(\Rightarrow C_{M_{NaOH}}=C_{M_{Na_2CO_3}}=\dfrac{0,15}{0,15}=1\left(M\right)\)

\(n_{CO2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)

Pt : \(CO_2+2NaOH\rightarrow Na_2CO_3+H_2O|\)

         1            2                   1              1

       0,3         0,6

\(n_{NaOH}=\dfrac{0,3.2}{1}=0,6\left(mol\right)\)

200ml = 0,2l

\(C_{M_{ddNaOH}}=\dfrac{0,6}{0,2}=3\left(M\right)\)

 Chúc bạn học tốt

Bài 7:

Ta có: \(\left\{{}\begin{matrix}n_{CO_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\\n_{NaOH}=0,2\cdot1=0,2\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\) Tạo 2 muối

PTHH: \(CO_2+2NaOH\rightarrow Na_2CO_3+H_2O\)

                 a_______2a__________a              (mol)

            \(CO_2+NaOH\rightarrow NaHCO_3\)

                 b_______b__________b       (mol)

Ta lập HPT: \(\left\{{}\begin{matrix}a+b=0,15\\2a+b=0,2\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}a=0,05\\b=0,1\end{matrix}\right.\)

Mặt khác: \(m_{dd}=m_{CO_2}+m_{ddNaOH}=0,15\cdot44+200\cdot1,25=256,6\left(g\right)\)

\(\Rightarrow\left\{{}\begin{matrix}C\%_{Na_2CO_3}=\dfrac{0,05\cdot106}{256,6}\cdot100\%\approx2,1\%\\C\%_{NaHCO_3}=\dfrac{0,1\cdot72}{256,6}\cdot100\%\approx2,8\%\end{matrix}\right.\)

Bài 8:

PTHH: \(RCO_3+2HNO_3\rightarrow R\left(NO_3\right)_2+CO_2\uparrow+H_2O\)

Giả sử \(n_{RCO_3}=1\left(mol\right)\) \(\Rightarrow\left\{{}\begin{matrix}n_{HNO_3}=2\left(mol\right)\\n_{R\left(NO_3\right)_2}=1\left(mol\right)=n_{CO_2}\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}m_{ddHNO_3}=\dfrac{2\cdot63}{20\%}=630\left(g\right)\\m_{R\left(NO_3\right)_2}=R+124\left(g\right)\\m_{CO_2}=44\left(g\right)\end{matrix}\right.\) \(\Rightarrow C\%_{R\left(NO_3\right)_2}=\dfrac{124+R}{R+60+630-44}=0,26582\)

\(\Leftrightarrow R=65\) (Kẽm) \(\Rightarrow\) CTHH của muối cacbonat là ZnCO₃

\(n_{CO_2}=0,15mol\)

\(n_{NaOH}=0,35mol\)

 \(T=\dfrac{n_{OH^-}}{n_{CO_2}}=\dfrac{0,35}{0,15}=\dfrac{7}{3}>2\)\(\Rightarrow\) tạo muối \(Na_2CO_3\)

    \(NaOH+CO_2\rightarrow Na_2CO_3+H_2O\)

      0,35        0,15      0,15           0,15

\(\Rightarrow\)\(OH^-dư\) 0,2mol.

\(m_{ddsau}=0,35\cdot40+0,15\cdot44-0,15\cdot18=17,9g\)

\(C\%_{saup}\)\(_ư\)\(=\dfrac{15,9}{17,9}\cdot100=88,83\%\)