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Kate Zeile 2D
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Joined: Sat Jul 22, 2017 3:01 am


Postby Kate Zeile 2D » Sat Jan 13, 2018 8:32 am

How does sublimation occur? In other words, how can a subliming substance just skip the liquid phase?

Vivian Nguyen
Posts: 66
Joined: Fri Sep 29, 2017 7:04 am
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Re: Sublimation

Postby Vivian Nguyen » Sat Jan 13, 2018 9:12 am

Yes, sublimation occurs when the phase change goes directly from solid to gas. It occurs in the right conditions where the pressure is low enough below the triple point on a phase change diagram. ... /Phase.gif However, this is all I can remember from high school chemistry, so if someone else would like to add more that'd be great!

Luke Bricca 1H
Posts: 30
Joined: Fri Sep 29, 2017 7:06 am

Re: Sublimation

Postby Luke Bricca 1H » Sat Jan 13, 2018 10:05 am

Follow up question: what is the triple point on a phase change diagram? In its definition it says that it's when all three phases of a substance "coexist in thermodynamic equilibrium," but what does that mean?

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Joined: Sat Jul 22, 2017 3:01 am

Re: Sublimation

Postby RussellChin_3A » Sat Jan 13, 2018 11:14 am

The triple point is exactly what it means: when all states of a substance exists at once. But like sublimation, it must occur in certain conditions

Scott Chin_1E
Posts: 55
Joined: Sat Jul 22, 2017 3:00 am

Re: Sublimation

Postby Scott Chin_1E » Sat Jan 13, 2018 11:16 am

You're correct in that the Triple Point is the point in which a substance can exist in all three states of matter. Even more so, this is the minimum pressure that is required for a substance to remain a liquid. You can think of this as a reference point in seeing phase changes, for example at pressures below the triple point when solid ice heated, it will sublimate. This is probably pretty ambiguous and vague but I'm sure Professor Lavelle will review this once we get into Thermodynamics and equilibria.

You should watch a video on water's Triple Point! It's actually a pretty interesting concept to witness.

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