Here’s the thing they showed on CSI - a crime tech picks up some “dirty ice” at a crime scene and puts it into a sample jar. Later the ice is gone and they realize it was dry ice. So, would that be possible without exploding the jar?
The sample looked about the size of an ice cube, and the jar about the size of a coldcream jar.
Depends on how tight the lid was, I guess.
If the lid was tight, I’d expect a big HISSS! when they opened the jar, at the absolute least. My WAG though, is a roughly cubic inch of dry ice would yeild enough CO[sub]2[/sub] gas at room temperature to pose a sigificant threat to a small sealed container’s structural integrity.
But, does *CSI * ever get real science right?
Disclaimer: I’m doing this all without a calculator, since the OP just wants to know if the jar would explode. My numbers will thus be rough approximations. That should be easy enough.
I see that dry ice has a density of “1.2 to 1.6 kg/dm^3”. Call that 1.5 g/cm^3. Let’s say the ice cube is 20 cm^3 in volume – that’s approximately an inch cubed. That gives 30 grams of CO2.
30 grams of CO2 at 44 grams/mol is about .7 moles of CO2. At normal temperature and pressure, one mole of gas has a volume of about 22 liters. That dry ice cube would then take up a volume of around ~15 liters once expanded. If you confine it to a medium size half-liter jar, the pressure in the jar with no leaks would be around 30 atmospheres. That’s definitely more than enough to burst your average glass jar.
How could they not tell the difference between ice and dry ice?
I would expect for the seal to fail before the glass, depending, of course, as gotpasswords alludes to, on how good the seal is.
My wife had some gas expansion problems but has made some adjustments to her diet to compensate.
If your wife is eating dry ice, she has more problems than a diet can cure.
But it may not be psychological, but a nutritional iron imbalance called pica.
Of course, if it is psychological, and you don’t have coverage for that, you can decide not to treat it, but train her to swallow other dangerous things like light bulbs and swords, and get her a job in the circus.
Santo Rugger: “How could they not tell the difference between ice and dry ice?”
They tried to cover this strange behavior by having the tech wear thick gloves and having the other tech ask him why he would collect it anyway. “Just being thorough.”
lazybratsche - Yes, that was what the OP was driving at. Although I suppose the seal could go first, especially if the lid warps or cracks. I knew a kid in high school who put baking soda and vinegar into a bottle and it blew up in his face, and he was in the hospital for ages getting back to normal.
It just seems like you’d be able to tell by how it looks, or the density.
Without doing the calculations, I’d imagine that solid CO2 would produce more gas per unit volume than baking soda and vinegar. Especially since the vinegar he used was probably only 5%. So, addressing your OP, yes, it is possible for contained CO2 to make a container blow up in somebody’s face. However, as mentioned earlier, the seal has a large influence on weather or not it is possible for the dry ice to sublimate without bursting the container.
Indeed - the two are only superficially similar.
Or how it feels. Very obvious if you handle it bare-handed.
I hear it burns, bites and freeeeeezes.
But the most it would be able to reach is around 5 atm (if I remember my phase diagram right). CO2 stops sublimating at pressures over about 5 atm and starts melting. It’s not inconceivable that a jar could hold 5 atm of pressure. I sure as hell wouldn’t want to open it with liquid CO2 in there, but it might hold it.
The CSI should have never received certification. He should have KNOWN it was Dry Ice, aka solid CO2, since it is so very cold to the touch even with rubber gloves.
Pluse he also forgot to SEAL the container to prevent leakage.
Actually, in a closed container dry ice is really easy to liquify. We used to extract the oil from orange peels this way. This is something you can do at home with no problem. Only the strength of your hand is required. Of course, if there is too much dry ice and the seal is really good, the pressure will build enough that the container will explode, so don’t try it unless you know what you are doing. Chances are though, that the container would not be well sealed.
On the other hand, in my experience, it would take a real moron to mistake dry ice for real ice.
Well, your average small sized water bottle (larger than a cold cream jar) will explode with a chunk of dry ice small enough to fit through the opening. (smaller than an ice cube.) Don’t try this at home kids. I would expect a glass jar to be stronger, but maybe somebody else knows more about that.
Beano seems to work…
Only if you screw thw cap on really tightly, and you probably wouldn’t do that unless you were planning on producing a bang.
Probably the real problem with this scenario, is that water ice and dry ice don’t even remotely behave the same way so only an idiot would make this mistake. Such an idiot would not be on the investigative branch of the police force.
The phase diagrams I’ve found show the pressure required for liquid CO2 at room temperature to be more in the range of 8 atm. That’s over 100 psi, and there’s certainly a chance of the jar rupturing. More likely it will pop the seal a bit and vent rather than explode.
True, but this liquid would eventually evaporate. Around room temperature, you won’t have any liquid CO2 below ~80 atm, IIRC.
Actually I should amend that slightly. From here, you have liquid CO2 around 60 psi at room temperature.
Since dry ice presumably starts below room temp, getting liquid CO[sub]2[/sub] in a bottle is not a big deal. I’ve done it. It is an interesting, if somewhat limited method for organic extractions. The advantage is that no solvent is left behind.