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## Teaching Practice of Analytical Chemistry Laboratory Based on Heuristic Teaching Method: Taking the Determination of Total Alkali Content in Soda Ash as an Example

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Abstract

Taking the determination of total alkali content in soda experiment as an example, we use heuristic teaching method to introduce problems, aiming at guiding students to think and discuss, to actively explore and solve problems, to cultivate creative learning and lifelong learning ability and scientific behavior habits. This approach can help to lay a solid foundation for subsequent laboratory course and scientific research work in the future.

Keywords： Analytical chemistry laboratory ; Heuristic teaching method ; Creative study ; Lifelong learning

LIU Xia. Teaching Practice of Analytical Chemistry Laboratory Based on Heuristic Teaching Method: Taking the Determination of Total Alkali Content in Soda Ash as an Example. University Chemistry[J], 2018, 33(1): 21-23 doi:10.3866/PKU.DXHX201709003

## 1 注重传授科学研究方法培养学生的科研能力

“纯碱中总碱量的测定”是以甲基橙或甲基橙-靛蓝混合指示剂，用HCl (约0.1 mol·L−1)标准溶液测定纯碱中碳酸钠质量分数。这虽然是一个经典的滴定分析实验，但我们将其设计成了探究性实验，在课堂上营造浓厚的科学研究气氛，调动了学生探究未知的兴趣和积极性。授课时以阐述实验原理为切入点，采取提问的方式要求学生讲解实验原理及实验内容，并在黑板上写出滴定反应及计算碳酸钠质量分数的公式：

${\rm{CO}}_3^{2 - } + 2{{\rm{H}}^ + } = {{\rm{H}}_2}{\rm{C}}{{\rm{O}}_3} \to {\rm{C}}{{\rm{O}}_2} \uparrow +{{\rm{H}}_2}{\rm{O}}$

$\omega \left( {{\rm{N}}{{\rm{a}}_{\rm{2}}}{\rm{C}}{{\rm{O}}_3}} \right) = \frac{{\frac{1}{2}c\left( {{\rm{HCl}}} \right)V\left( {{\rm{HCl}}} \right)M\left( {{\rm{N}}{{\rm{a}}_{\rm{2}}}{\rm{C}}{{\rm{O}}_3}} \right)}}{{{m_{\rm{s}}}}}$

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