If I were to put a piece of Dry Ice in a sealed soda bottle, eventually the bottle would blow the cap off. If you were to put the Dry Ice in a sealed container that could not blow the cap off, or “explode”, would the pressure build so great that the Dry Ice would stop sublimation (melting)?
Would I have a piece of Dry Ice which would eventually reach room temperature and stay a solid? How much pressure would the container reach ( at room temperature)?
Rough estimate: You’d need about 7500 bar (about 109 000 psi) at 293 K, according to my rough reading of a logarithmic phase diagram for CO[sub]2[/sub].
It would clearly depend on the mass of CO2 and the volume of the container. Here’s a diagram that gives answers for various conditions.
Well, if we want to assume that my figure is correct (and even if it isn’t, it’ll be simple enough to alter the math using a more suitable number) and assume a 1 L container, and 293 K…
PV/RT=n
(7400 atm)(1 L)/(0.08204 L atm K[sup]-1[/sup] mol[sup]-1[/sup])(293 K)=308 mols of CO[sub]2[/sub]
Wikipedia says that low-ball density of dry ice is 1.2 kg/dm[sup]3[/sup]. 308 mols of dry ice would be about 13.5 kg. Since a L is a dm[sup]3[/sup] the world around, it doesn’t look like we’d even be able to fit enough dry ice into a theoretical container in order to build up the requisite pressure due to its own sublimation, so we would have to charge the container with some pressure from another source.
Assuming my calculations are correct, I’m never very confident about them on the Dope.
I’m guessing it’d actually turn into a liquid? Putting enough pressure on it to keep it solid might be huge.
I’m not a physicist, but it seems to me if you got yourself an infinitely strong steel jar without a weakness at the lid, that the substance cannot stay cool, the laws of thermodynamics and all being inviolable. So it would have to reach room temperature. Whether it would be solid or liquid, I cannot guess.
The ideal-gas equation is not a good approximation when the computed gas density is greater than the condensed-phase density. You can get closer with a higher-order approximation like the van der Waals equation, which provides corrections to the ideal-gas equation that become important for CO[sub]2[/sub] at molar densities of a few mol/L: which makes sense, since as your calculations show, this is about when it starts getting close to the condensed phase.
But even the van der Waals equation can’t be taken seriously for condensed phases. You really just have to look at a density-pressure chart, like the one here.
At room temperature, CO[sub]2[/sub] doesn’t sublimate; there’s a stable liquid phase between about 70 and 7000atm. You can read the densities at the endpoints of the ~70atm liquid-vapor mix for the 300K line: about 300kg/m[sup]3[/sup] for pure vapor and about 700kg/m[sup]3[/sup] for pure liquid. (The liquid is not very dense at this pressure since this is close to the critical point.) So if you put less than ~0.3kg into your 1L container, it will be a gas at room temperature; if you put between 0.3 and 0.7kg it will be a liquid-vapor mix, and if you put more than 0.7kg it will be liquid, solid, or a combination of the two. From the pressure-density diagram on that page it looks like the liquid phase has maximum density somewhere around 1kg/L, so that’s probably about the density when you’ll start getting solid CO[/sub]2[/sub] at room temperature, if your pressure vessel is strong enough.
Also, from personal experience, a 2L soda bottle 1/4 full of dry ice and water will not “blow the cap off”. It FUCKING EXPLODES! As in, the largest fragments of plastic you will find will be something like an inch or two square. It also makes a sound like a goddamned cannon being fired. Also works with glass bottles. I used to make dry ice at work and bring it to parties, fill a bottle 1/4 of the way up with dry ice and water and then throw it on the porch while everyone watched through the window. Fun times.
Sorry but your numbers must be wrong. Your calculations look fine so I’m guessing your density is to low. If I remember correctly from chem the triple point for CO2 is around 6atm when you account for the cooling inside the container from the dry ice itself. I’ve done it in class with a clear plastic tube plugged on one end and a valve on the other. It only took about 20ml (crushed) CO2(s).
Seconded. Pressure in CO2 bottles (liquid at boiling point) is around 2-300 psi at room temp.
I volunteer the good folks at Autoclave Engineering in Erie, PA, who sell as standard catalog items tanks that handle as much as 10,000 atmospheres (that’s 150,000 psi). Or at least used to…
I actually have some experience with this. It involves liquid CO2, not dry ice, but the rensity mush be about the same. This goes back 55 years, but I worked in a lab for an electron microscopist. Since the specimens had to be a vacuum, they had to be dried. Air drying would flatten the specimens from surface tension. My boss, one Tom Anderson, devised his own method for drying specimens without surface tension. Any substance has a “critical point”, a temperature above which there is only one phase, gas. And if you take a liquid and heat it to its critical point, the liquid becomes gas with no evaporation and no surface tension effects. There is a problem: the critical point of water is hundreds of degrees C and that would destroy biological specimens.
Essentially the drying method consisted of first replacing all the water by liquid CO2 and then raising the temperature of the sealed container to the critical point of CO2 (45 C, as I recall). Since water is immiscible with liquid CO2, the replacement is hard. So if you could find a liquid that is miscible with both water and CO2, you could first replace the water by that intermediate liquid and then that liquid by the CO2. In practice, there was no convenient single liquid, but we replaced the water by alcohol, then the alcohol by amyl acetate (using baths) and then put the specimen into what was called a “bomb”, a heavy steel cylinder maybe 4" long and 1" in diameter, with pipes and valves at each end. We then attached a liquid CO2 tank at one end, opened the valves and let the CO2 run through the specimen for a few seconds, then closed the valves at each end, detached the CO2 tank and dumped the bomb into a sink filled with hot water (it came out of the tap at 70 C). After minute the CO2 had turned to gas and we carefully opened the valves and pulled the specimen out. For more details, see http://www.springerprotocols.com/Abstract/doi/10.1385/1-59259-030-6:235
Lol, it’s how it works out every time. I think I’m going to be first on the scene with a useful answer but I go and get my density from Wikipedia and screw the whole thing up.
Dry ice bombs created by sealing a chunk of dry ice in a container like a glass bottle can produce a very loud bang and an impressive cloud of shrapnel. Enough so that the wiki article mentions that they are specifically outlawed in some jurisdictions. However, one wishes that the lawmakers drafting the quoted CA statute would have been more careful:
If arrested under that statute, I would be very tempted to contest it on the basis that the device did NOT cause an explosion by a chemical reaction, but by a physical effect.
This is a little crusade of mine. Nunavit Boy has it correct, this is a BOMB. I had the web of my thumb cut straight through and inch and a half down and my thumb broken in two places by one of these. I do not recommed this as a toy but hey, everyone has their own level of acceptable risk.
ETA the dry ice bomb that injured me was a 2L plastic bottle.
Maybe this is a hijack, but I’ve always been under the impression that there is no liquid phase for CO2. Can someone explain the conditions under which such an animal exists?
At pressures above 5.1 atmospheres. See the phase diagram and article text:
There is no liquid phase of CO[sub]2[/sub] at atmospheric pressure. It can exist as a liquid at higher pressures. Omphaloskeptic’s link offers some more information.
How long does this [a dry ice bomb] take to occur?
Not too long, depending on the size of the container and the size of the chunk of dry ice.
Plenty of potential Darwin Award recipients demonstrating on youtube:
http://www.youtube.com/results?search_type=&search_query=dry+ice+bomb&aq=f
*** Ponder