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Understand MAgnesium nitride correctly

wallpapers News 2021-10-29
As we all know, chemical experiment teaching plays a very important role in chemical teaching activities. From strengthening teachers' professional knowledge, and from the students' cognitive development levels, change student's study way, improve students' initiative and enthusiasm of learning and to participate in activities, suggest contributors in writing textbooks of senior high school or when writing teachers teaching resources, increase in air ignite Mg generates MAgnesium nitride inquiry experiment [2], and make the following instructions:
When the magnesium strip is ignited in the air, not only magnesium oxide is produced, but also magnesium nitride. MAgnesium nitride is a pale yellow powder or lump. The relative density is 2.712, decomposition at 800C, sublimation at 700'C in a vacuum, magnesium nitrite is an ionic compound, hydrolysis in water: MAgnesium nitride+6H2O= 3Mg(OH)2+2NH3↑ soluble in acid, insoluble in ethanol.
This experiment can also be used as an after-school chemical exploration experiment activity.
The author believes that the development of the new curriculum, we need to firmly adhere to the experiment, the most basic, the most effective, the most can reflect the discipline of the position, let us do some practice for the development of the new chemistry curriculum, this is the top priority.
MAgnesium nitride in the experiment
Due to the limitation of students' cognitive level, teachers in junior high school only explained that the product is MgO, and in senior high school, when Mg is burned in the air, they further explained that MAgnesium nitride is generated. In recent years, there are many books and periodicals on the knowledge of MAgnesium nitride. Due to improper methods, many teachers did not see the light yellow powder generated during the experiment, and chose to avoid or imagine that Magnesium nitride should be generated by "talking instead of doing".Faced with the question "why can't you see the light yellow MAgnesium nitride generated when Mg bar is ignited in the air", some even make "MAgnesium nitride can be decomposed at 800"C" Mg and N2. If the flame temperature of Mg combustion is higher than 800C, MAgnesium nitride can be decomposed into Mg and N2 at 800C even if it is generated. If the flame temperature of Mg combustion is higher than 800C, the generated MAgnesium nitride will be decomposed even if MAgnesium nitride is generated, that is, the final product of combustion is MgO.

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