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Dry ice sublimates at -78.5°C, while the lowest temperature registered is about -89.2°C around the Vostok station in Antarctica. Imagine a person living on that station on that day (or night, since it was measured during the polar night).

If that person goes outside, would they find any dry ice crystals laying on the ground?

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The equilibrium vapor pressure of carbon dioxide at -80 C is about 1 bar. The partial pressure of carbon dioxide in air is about 0.0004 atm. This tells you that CO2 will not sublime from air at -80 C.

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  • $\begingroup$ That's why I always make sure to bring a sealed box of carbon dioxide when I vacation in Antarctica. $\endgroup$ – JMac Mar 18 at 17:48
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    $\begingroup$ While this answer is completely correct, I feel obliged to point out that drawing comparisons between two values in different units (atm vs. bar) is Not A Best Practice, particularly when they're not related by a standard SI prefix. $\endgroup$ – Michael Seifert Mar 18 at 17:58
  • $\begingroup$ Oops. I meant for the first to be atm. $\endgroup$ – Chet Miller Mar 18 at 18:01
  • $\begingroup$ So if I was brewing beer (what else is there to do at Vostok?), and thus had a container of carbon dioxide, which naturally happens during brewing, that container could have developed CO2 crystals, while it slowly deflated. $\endgroup$ – Cort Ammon Mar 18 at 22:00
  • $\begingroup$ Yes, if the pressure of pure CO2 in the container is higher than the equilibrium vapor pressure of CO2 at the temperature of the CO2. $\endgroup$ – Chet Miller Mar 18 at 22:28

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