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Itoero

Hot ice

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I bought several heat pads that contain sodium acetate trihydrate...to make hot ice.

But what form of 'stress' creates the ice?

Can I open such a small plastic pad with a scissors and pour it gently in a glass cup?

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1 hour ago, Itoero said:

Can I open such a small plastic pad with a scissors and pour it gently in a glass cup?

Yes as long as it is above the melting point of the material (presumably hydrated sodium acetate)

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2 hours ago, Itoero said:

Can I open such a small plastic pad with a scissors and pour it gently in a glass cup?

Yes. But cheaper would be to get sodium hydroxide and acetic acid alone, and mix them in the right proportions. They are used in kitchen and toilet for unblocking pipes.

 

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9 hours ago, Sensei said:

get sodium hydroxide and acetic acid alone, and mix them in the right proportions.

That would probably result in an explosion- certainly a very violent reaction

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15 hours ago, John Cuthber said:

That would probably result in an explosion- certainly a very violent reaction

In typical kitchen we have 10% acetic acid by volume. I used 5 mL of 10% acetic acid and mixed it with sodium hydroxide. Reaction increased temperature inside of the baker from 21.7 C to 51.7 C, and then started dropping. When it reached 31 C, I added 10 mL more acetic acid 10%, temperature raised again to 37 C, and then started dropping.

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On 11/29/2018 at 9:33 PM, Sensei said:

...acetic acid alone...

is not acetic acid with 10 times as much water.

Would you like to do the experiment you described originally?
It would be interesting, but hazardous.
 

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On 29/11/2018 at 6:49 PM, Itoero said:

Can I open such a small plastic pad with a scissors and pour it gently in a glass cup?

Any residues or scratches on the glass might cause the solution to crystallise. But that's OK, you can just heat it again to reverse that.

https://en.wikipedia.org/wiki/Sodium_acetate#Heating_pad

On 29/11/2018 at 6:49 PM, Itoero said:

to make hot ice

Why are you calling this "ice"? Just because it is crystalline?

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On ‎29‎/‎11‎/‎2018 at 9:38 PM, John Cuthber said:
On ‎29‎/‎11‎/‎2018 at 7:49 PM, Itoero said:

 

Yes as long as it is above the melting point of the material (presumably hydrated sodium acetate)

Ah yes, the melting point is about 58°C. I can do the plastic pads in hot water before I go cutting and pouring.

 

On ‎29‎/‎11‎/‎2018 at 10:33 PM, Sensei said:

Yes. But cheaper would be to get sodium hydroxide and acetic acid alone, and mix them in the right proportions. They are used in kitchen and toilet for unblocking pipes.

 

It's often made with vinegar and baking soda...isn't that cheaper and safer?

 

3 hours ago, Strange said:

Any residues or scratches on the glass might cause the solution to crystallise. But that's OK, you can just heat it again to reverse that.

Ok, thx, then I definitely have to heat the heating pads before I cut them open.

 

3 hours ago, Strange said:

hy are you calling this "ice"? Just because it is crystalline?

Because other people call it 'hot ice'. It's a trihydrate so it makes a lot of sense to call it 'ice'.

How does the crystal structure look?

Is it basically H2O- Ice with an impurity?

Edited by Itoero

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