Endothermic Reaction—Freeze a Beaker to a Board
- Page ID
- 128807
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|
Required Training |
Required PPE |
|---|---|
|
UC Lab Safety Fundamentals |
Lab coat, safety glasses/goggles, nitrile gloves |
|
Equipment |
Chemicals |
|
100 mL beaker |
17 g Ammonium Nitrate |
|
Wooden block |
32 g Barium Hydroxide |
|
Glass stir rod |
|
|
DI squirt bottle |
|
Procedure:
- Set the beaker on top of the wood block.
- Pour the contents of the two vials, ammonium nitrate and barium hydroxide, into the beaker simultaneously.
- Stir if necessary.
- This endothermic reaction will condense water vapor from the air between the bottom of the beaker and the wooden block and freeze it.
- If it is too dry, water can be sprayed on the block with a squirt bottle.
Discussion:
The temperature of this reaction can drop to -25C to -30C.
Hazards:
Spent solution should be covered and put into a fume hood as soon as possible. This reaction releases ammonia gas. Soluble barium compounds are toxic to blood. Consult MSDS for full detail.
SOP:
Nitrates – Ammonium Nitrate
Disposal (by Storeroom)
Cover the beaker with parafilm after the demo and put the entire set-up into a large beaker during transit to prevent spilling. Return this Barium solution for proper disposal.