Sublimation

[Kate Zeile 2D]

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

[Vivian Nguyen]

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. http://www.kentchemistry.com/images/lin ... /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]

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?

[RussellChin_3A]

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]

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.