h brushes.Put the separate black power in the cells into the beakers.
（2）Separate NH４Cl、ZnCl2 from mixture.Then recycle them and test them.
①Get from the black power the crystal mixture of NH４Cl and ZnCl２
②Do a simple experiment to prove that there are NH４＋ and Ｚｎ２＋ in the crystal,and fill the experiment record.
Explanation:［Zn（OH）２ is a amphiprotic oxide.It can dissolve in ammonia water and change into Zｎ（ＮＨ３）４２＋］
Step Appearance Conclusion
①Dissolve the mixture in Ｈ２Ｏ — —
②Drop NaOH ↓and↑ ＮＨ４＋
③Continue to drop NaOH ↓disappear Ｚｎ２＋
（3）Separate ＮＨ４Ｃｌfrom ＺｎＣｌ２ by heating.
（4）The main parts of the left black powder are MnO２、carban black and some organics.We can get off the impurities by weightemperature buring.
最后学生谈了自己的opinion:For our homeland,please protect the environment,and we must not neglect the bad effect of the used dry cells to our surroundings。
课后，学生用英语撰写了小论文，制成双语课件，贴到班级网页中的化学论坛里，进行在线交流。他们还建议学校开设理科实验班的物理、生物等双语选修课，引起了领导的重视。
通过一段时间的实践和探索，我们发现在第二课堂教学中由于教学语言的多样性，绝大多数学生都表现出很高的学习兴趣，听课时更为专注，学生互动的同步性更强。目前我校参加双语教学研究的老师越来越多，我们准备组织课题组的老师汇编已有的教案和课堂实录，探索研究双语教学在不同层次上的教学模式和面上的推广。
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