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Second, the material problem.
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Third, the experimental questions
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This part of the extended information mainly examines the knowledge points made by heating:
The mixture of solid ammonium salt and alkali is heated, and the reaction device is a solid+solid heating gas making device. Including test tubes, alcohol lamps, iron racks (with iron clips), etc. Purification device (can be omitted): dry with alkali lime.
Acquisition equipment:? Downward exhaust method, full measurement method is to put wet red litmus test paper on the test tube mouth, and the test paper turns blue; Or put a glass rod soaked in concentrated hydrochloric acid at the mouth of the test tube, which will produce white smoke. Tail gas device: When collecting, a cotton ball is usually plugged in the pipe mouth, which can reduce the convection speed between NH3 and air and collect pure NH3.
Nh4no 3 can't react with Ca(OH)2 to produce ammonia. Ammonium nitrate is easy to explode when heated, and its products are related to temperature, which may produce NH3, N2, N2O and NO? [5]?
In the laboratory, NaOH and KOH can't replace Ca(OH)2 to generate NH3. Because NaOH and KOH are strong bases, moisture absorption (deliquescence) is easy to agglomerate and it is not easy to fully contact and react with ammonium salt. In addition, KOH and NaOH are very corrosive, and heating will corrode glass instruments, so NaOH and KOH are not used to prepare NH3 instead of Ca(OH)2.
When ammonia gas is collected in the test tube, cotton needs to be blocked. Because the diameter of NH3 molecular particles is small, it is easy to have convection with air. The purpose of cotton plugging is to prevent NH3 from convection with air and ensure the purity of collection. Reduce air pollution caused by NH3.
Alkaline lime is used to remove water vapor from NH3 instead of concentrated H2SO4 and solid CaCl2 in the laboratory. Because concentrated H2SO4 reacts with NH3 to generate (NH4)2SO4. NH3 reacts with CaCl _ 2 to produce CaCl _ 2·8NH _ 3 (calcium octacarbamate). Calcium chloride +8 ammonia = calcium chloride 8 ammonia.