Bài 3:
PTHH: \(CaCO_3\xrightarrow[]{t^o}CaO+CO_2\)
Ta có: \(\left\{{}\begin{matrix}n_{CO_2}=n_{CaCO_3}=\dfrac{20}{100}=0,2\left(mol\right)\\n_{NaOH}=0,5\cdot0,56=0,28\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\) Tạo 2 muối
PTHH: \(CO_2+NaOH\rightarrow NaHCO_3\)
a_______a___________a (mol)
\(CO_2+2NaOH\rightarrow Na_2CO_3+H_2O\)
b_______2b__________b (mol)
Ta lập HPT: \(\left\{{}\begin{matrix}a+b=0,2\\a+2b=0,28\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}a=0,12\\b=0,08\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}C_{M_{NaHCO_3}}=\dfrac{0,12}{0,5}=0,24\left(M\right)\\C_{M_{Na_2CO_3}}=\dfrac{0,08}{0,5}=0,16\left(M\right)\end{matrix}\right.\)
Bài 2:
Ta có: \(\left\{{}\begin{matrix}n_{CO_2}=\dfrac{11,2}{22,4}=0,5\left(mol\right)\\n_{NaOH}=0,15\cdot0,3=0,045\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\) Tạo muối axit, CO2 dư
Bảo toàn Natri: \(n_{NaHCO_3}=n_{NaOH}=0,045\left(mol\right)\) \(\Rightarrow m_{NaHCO_3}=0,045\cdot84=3,78\left(g\right)\)
