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Hot Ice

Kzoppistan

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What's the word of the day, kids?

Sodium Acetate!

You may be familiar with this versatile chemical compound as the ingredient in re-usable winter time pocket hand warmers.

But did you know it is also what they sprinkle on potato chips to give it the classic 'salt and vinegar' flavor?

That it is, in the dilute trihydrate form, the remains of your science fair volcanoes?

Or that it is used as a concrete sealant, or to neutralize sulfuric acid, or retard the vulcanization process?

Or, perhaps most visually fascinating, that you can make heat-generating crystalline structures known as 'hot ice'?

Well now you do, and I've got some right here. And so can you!

Sodium Acetate, NaOAc, is simply the combination of sodium bicarbonate, your classic baking soda, and acetic acid, commonly known as vinegar.

I did this experiment over the course of the last several hours and even though it was a heck of project (though it shouldn't have been), it was totally worth it when I finally saw my solution turn from a liquid into a spindly hot crystal in seconds right before my very eyes.

I'll probably never be the kind of person who can pull off a great plan by carefully plotting all the steps and then following through on them for perfect results, efficiently, with no snags or unexpected results. Unfortunately I lack (severely) the patience for this. I can barely follow a baking recipe. Thankfully, trial and error (and error and error) is our friend.

This process is remarkably simple, add baking soda to vinegar, let the reaction settle, and then boil it down to remove excess water. How hard is that, right? Well, I found out. After getting a rough outline of how this is done while in the process of researching glacial acetic acid, I tried it with the materials I had on hand. The first batch was going swimmingly, (and fun, if you like massive fizzy carbon dioxide reactions) until the mason jar I had exploded while heating, soaking the stove and me with broken glass and vinegar, necessitating a clean-up and trip to the trash cans outside. The jar wasn't under pressure, it was just an old one I found on the side of the road while jogging one morning. Seemed sturdy enough. *shrug* Humorously, it left a perfect ring of glass around the base upon which the words molded in the glass read CHINA as if to mock me (seriously, China, stop, your exports suck).

Using some of what I had left, I made a much smaller batch in a metal dish. 45 minutes of boiling later, I had a lot of crystal mush, which I then microwaved on a plastic dish to drive off the remaining water. Scraping the dry white powder crystals from the plate with a spoon, which took enough work that I almost got out my id card from my wallet (and also almost made me forget what I was doing) the first part I deemed successful. However, making a solution with the crystals, heating it, and then cooling it in the fridge (and then spilling some of it while trying to pry the lid off, damn it) did not produce the hot ice effect I expected. Nothing. It was a dud.

I was pretty disappointed. But not defeated. I found a more exact formula, realized I would need more supplies, and 10 o'clock at night in January at 2 below, I geared up and marched the 2 mile round trip to Krogers to buy several gallons of white distilled vinegar, and pick up some groceries. I had also planned to buy a metal pot, as the only one I had was holding old soup. I would have to clean the pot to use it, and my large kitchen sink was currently filled to the brim with soaking eggshells (don't ask, it's something else I'm doing). However, the prices on cooking gear are exorbitant at Krogers, so I passed on that.

Getting back, cleaning the eggshells, the sink, and then the pot. At this point I was pretty exhausted, which led to rushing the mixture and getting my very own private baking soda volcano all over my work bench. Wonderful. An hour later of boiling, checking the amount, boiling, ect. It was finally done. 1 liter boiled down to about 150 ml. I placed in the fridge to let it cool. Checking it. Nothing. Crap. So I put it back on the stove and drove off another 25 ml. I put it back in the fridge again and then sat down on the bed to wait. Where I promptly passed out.

This morning, awaking confused and fully clothed (for once), I had no other thoughts: I sat up, immediately walked to the kitchen, removed the jar, carefully this time, pried off the lid, and there, within seconds due to the shaking of the jar, I saw the most glorious sight: this chemical compound forming, growing, in some exact mathematical self-replicating structure, long spindles of crystal lattice until it was a giant block of solid matter as if it were in stop motion animation right before my groggy eyes. Amazing. Touching my hand to the jar, it went from almost frozen cool from the fridge to a warm comforting glow. It was better than Christmas.

So not only is it educational, but it's also safe for the kids. Below is a great link very quickly explaining the procedure. Have fun!



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