Dry ice and diamond?

When you want to seperate dry ice and diamond, you can choose to heat their solid on an evaporating dish/ Then the solid left is diamond. When the dry ice( carbon dioxide gas) evaporates and touches a glass surface, it condenses and even changes to solid. I wonder why a glass surface can make dry ice formed. Is not that a very low temperature has to be provided when dry ice formed?

Answer:
What is happening is the dry ice is sublimating, but is still relatively cold. This cold CO2 is mixing with the air, cooling it down. Air usually contains a certain amount of water that is below the saturation point at normal room temperature, cooling this air will make the air supersaturated with water, and it will leave the "solution" in the form of liquid water (on another topic this mechanism is how dew is formed at night).

Now dry ice has a sublimation temperature well below 0 °C (-78 °C at atmospheric pressure), so it would be possible for the air and the surface of the glass to be cooled enough to freeze the newly formed liquid water on the surface of the glass.
It doesn't form dry ice, it forms water ice. The condensation in the glass is no different than that in the glass of a cold drink by the beach. Since the temperature is steadily low not only does it condenses but freezes; it is still water nonetheless.

Dry ice sublimates. That means that from solid to gas it does not have to pass through liquid that is why it is so popular in ice cream carts that are not powered, because it leaves no liquid residue.
What your seeing is probably just the moisture in the air freezing on the glass.
I M O you are not viewing new dry ice reforming on the glass. You are seeing water condensation from the warm room temp. air in the room freezing on the glass due to the low temp. of the evaporating dry ice. You only need 32° F (O° C) to freeze water. What makes you think the new solid is CO2 and not H2O? When it finally melts does it drip down or does it evaporate away as a gas? But that's just IMO!

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