CALCULATION OF CONDITIONAL EQUILIBRIUM IN SERIAL MULTIPLE PRECIPITATION OF METAL SULFIDES WITH HYDROGEN SULFIDE STREAM GENERATED FROM SODIUM SULFIDE: A DIDACTIC TOOL FOR CHEMISTRY TEACHING

Química Nova

Bellová, Renata¹  Melicherčíková, Danica¹  Catholic University in Ružomberok, Ružomberok, Slovak Republic¹  Tomčík, Peter¹ 

关键词:  visual perception;    laboratory demonstrations;    equilibrium;   

DOI  :  10.5935/0100-4042.20160062

学科分类：化学（综合）

来源: Sociedade Brasileira de Quimica

【 摘 要 】

Hydrogen sulfide is presented in textbooks as toxic, environmentally unacceptable species, however some positive effects in human metabolism were discovered in the last decades. It is important to offer students also some new information about this compound. As didactic tool in this case may serve serial precipitation of Cd2+, Cu2+, Zn2+, Mn2+ and Pb2+ ions forming various colored sulfides in bubblers with chemically generated hydrogen sulfide stream. This experiment has strong and diverse color effect for enhancing the visual perception to motivate students to understand more abstract and complex information about hydrogen sulfide. It also may be helpful in analytical chemistry courses for conditional precipitation equilibrium teaching and calculations.

【 授权许可】

Unknown