Endothermic reaction (Ammonium chloride & barium hydroxide)

Morning all,

So I tried this using the small chemical pots we have, stirring for 30 seconds vigorously and nothign happened.

I then used the stock chemicals we have and this worked perfectly.

Just curious to know if the above two chemicals might have 'gone off' or perhaps one might have been mislabeled. I now have a beaker with two chemicals mixed. Although come to think of it, the Barium hydroxide looked different from the stock bottle to what was in the container. I wonder if there is a hydrous and anhydrous form?
 
Morning all,

So I tried this using the small chemical pots we have, stirring for 30 seconds vigorously and nothign happened.

I then used the stock chemicals we have and this worked perfectly.

Just curious to know if the above two chemicals might have 'gone off' or perhaps one might have been mislabeled. I now have a beaker with two chemicals mixed. Although come to think of it, the Barium hydroxide looked different from the stock bottle to what was in the container. I wonder if there is a hydrous and anhydrous form?
Be very careful when you do this Jimbob - it can get very cold. Best place the container on a heatproof mat.
 
Yes I did, as per the RSC guidelines:

'Solid hydrated barium hydroxide is mixed with solid ammonium chloride in a beaker. An endothermic reaction takes place to produce a liquid, with the evolution of ammonia. The temperature drops dramatically to about -20 °C.'

Which is why I was miffed and asked the question :D
 
Yes I did, as per the RSC guidelines:

'Solid hydrated barium hydroxide is mixed with solid ammonium chloride in a beaker. An endothermic reaction takes place to produce a liquid, with the evolution of ammonia. The temperature drops dramatically to about -20 °C.'

Which is why I was miffed and asked the question :D
I use quite big quantities - 100g Barium Hydroxide and 50g of Ammonium Thiocyanate.
Works perfectly.

https://edu.rsc.org/exhibition-chemistry/chilling-effects/2000044.article
 
We do this one regularly. A couple of scoops of each into an Erlenmeyer flask, then mixed with a stirring rod. We get our students to hold the flask in their palm to feel the reaction. The small quantities allow for it to be safe. The warmth in their hands doesn't allow the reaction to get too cold. This is where they also learn to waft to get the odour.

We'll also use this same demo, but place the flask on a small piece of wood in a spot where we've added some water. The reaction will freeze the water and secure the flask to the wood, allowing us to pick up the flask with the wood still attached.

Good times!
 
It's definitely to do with water. I had a demo failed despite double checking everything. I realized I used anhydrous barium hydroxide, when I repeated it with hydrated barium hydroxide it worked perfectly...
 
ammonium chloride can decompose and give off ammonia - in the small pots, the compound may be getting too warm and giving off ammonia?
 
5.5g Ammonium chloride
16g Barium hydroxide.
Mix together with a stirring thermometer, (it becomes a paste). I place the beakers onto a wood block with a few drops of water underneath it and the beaker freezes to the block. Looks impressive when you lift the beaker and the block comes up with it. It usually drops from +20 to -30 degrees
 
The barium hydroxide in the pots had altered to barium carbonate by absorbing CO2. It is a comon problem. I surprised you have anhydous barium hyroide which is more expensive..
 
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