Endothermic Dissolution of Ammonium Nitrate
Description: A crystalline solid is added to a beaker of cold water. Ice water is added to the surface of the beaker. Upon mixing, the water on the bottom of the beaker freezes the beaker to the surface it is resting on. The progress of the reaction can also be tracked with a temperature display.
NH4NO3(s) + H2O(l) → NH4+(aq) + NO3–(aq)
Source: UW Card Catalog, Kauffmann, G.B., Ferguson, C.A. Journal of Chemical Education
Year: 1988 Vol: 65 Page: 267
Keywords: Endothermic, Thermodynamics, Dissolution, Ammonium Salts
Rating: 
Hazard: Low
- Oxidizing solids
- Eye irritation hazard
- Specific target organ toxicity-single exposure – respiratory
Effectiveness: Average
- Secondary observations
- Good connection from demo to course material
- Results are hard to perceive without guidance
- High reliability
- Time to results is low
Difficulty: Low
- Simple procedures
- Simple manipulations for most to perform
- Use of concentrated acids and bases
- Demos in which display or recording is necessary
Safety Precautions:
- Eye protection required
- Gloves required
- Avoid exposure to dusts or droplets
Class: Thermochemistry
Division: General Chemistry
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