Endothermic Reactions of Barium Hydroxide and Ammonium Salts
Description: Endothermic reaction of barium hydroxide and an ammonium salt. Mix the two solids; they react, and the products dissolve in water of hydration. The reaction flask may be passed around for students to feel how cold it is.
This demonstration is also available on video and JCE “Chemistry Comes Alive!” Vol. 3 CD-Rom.
Source: Shakhashiri, B.Z. Chemical Demonstrations: A Handbook for Teachers of Chemistry
Year: 1983 Vol: 1 Page: 10
Keywords: Endothermic, Barium hydroxide, Ammonium salts, Hydration, Freezing
Rating: 
Hazard: High
- Aquatic toxicity hazard
- Acute toxicity hazard – oral, inhalation, dermal
- Skin corrosion hazard
- Serious eye damage
Effectiveness: Excellent
- Very good connection from demo to course material
- Results are clearly observable with guidance
- Superior reliability
- Counter-intuitive or engaging effects are seen
- Time to results is low
Difficulty: Medium
- Specific coordinated manipulations required
- Continuous stirring and precise methods required
- Toxic gas produced during manipulation
- Prior training recommended
- Multi-step sequential procedures
Safety Precautions:
- Eye protection required
- Cryogenic gloves required
- Lab coat recommended
- Perform in a well-ventilated area
- Downdraft hood recommended
- Absorbent materials on hand
- Sodium bicarbonate on hand
- Prevent release of reagents to the environment
Class: Spontaneous Endothermic Reaction
Division: General
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