Why doesn't Dry Ice leave water.....?

Question

when it melts?

Answer 1

Simple. Dry ice doesn't have any water in it. We call it dry ice, but it should be called solid carbon dioxide.
The word "ice" is misleading, but that's one of the joys of the English language.

Answer 2

I think many people missed the real question here, which is really a good one!

As everyone has indicated, dry ice is made of CO2, not water. So it sublimes from solid straight to gaseous CO2. However, dry ice is at -78ºC, which is less than the freezing point of water (0ºC). Therefore, you should expect some water from the air to condense out of the air and onto the dry ice, because it's so cold. As a matter of fact, this is exactly what happens...there is a small "puddle" of water left behind if dry ice is left in a humid environment.

The smoke and mist you see when dry ice is exposed to a humid environment is actually water condensing out of the air.

Again, good question! Thumbs up.

Answer 3

Dry Ice is not water ice, it is frozen carbon dioxide. It sublimes directly to a vapor at common room temperatures. The temperature of dry ice (CO2 or carbon dioxide) is -109 degrees F, so instead of melting it simply boils away. You can actually melt dry ice into a liquid but this would require pressurization and very low temperatures. At anything around normal room temperature and pressure it simply evaporates (boils off).

There is such a thing as liquid CO2.

Answer 4

Dry ice is frozen carbon dioxide or CO2. This is the same gas we exhale, plants inhale, and is the carbonation in our soda and beer. Dry ice is both denser and colder than ice made from water. Dry ice doesn't float in water and whereas water freezes at 32° F (0° C) CO2 freezes at -109.3° F (-78.5° C). That's mighty cold!

But what makes it "dry"? Well, a particularly interesting thing about dry ice is that it doesn't melt, it sublimates. This means that it goes directly from its solid frozen state to gas without first becoming a liquid. (At standard pressure and temperature of course) This recently sublimated super cold gas expands and lowers the air temperature it comes in contact with. Water vapor in the air condenses and forms fog.

Answer 5

Dry ice has the feature of "sublimation" which is the the change from solid to gas without passing the liquid state. As it breaks down, It turns directly into carbon dioxide rather than a liquid.

Answer 6

Dry ice is kind of a misnomer. Really, its CO2, not H20.

So, CO2 can't turn into H2O when it goes away. Actually, "dry ice" doesnt melt at all. Usually, it just turns into gas. Thats called sublimation.

Answer 7

Because dry ice isn't made of water or h 2 o. it is made from carbon di oxide so when it evaporates it turn directly into a gas leaving no liquid behind.

Answer 8

Many gases other than "Dry Ice" CO2 also sublimate: That is they go directly from solid phase to gaseous phase with no in-between liquid phase. CO2 is just one gas of many that does this. H2O does not because it is not a gas, but O2 by itself sublimates. It is doubtful you will ever casually see a piece of solid O2, H2 or He2 because of the combination of extremely low temperatures and high pressures that are needed to place them in a state of solidity. Some gases sublimate violently if their temperatures are raised too quickly. A chilled, solid chunk of gas, then raise to and above it's sublimating temperature in a closed container can end up exerting many thousands of pounds per square inch upon that container placing it in danger of rupture if it is not designed to hold that amount of gas in the original chunk at a specific, final temperature.

Answer 9

Dry ice is not water. It is carbon dioxide gas that is frozen to a solid. When it heats up, it turns back into a gas.

Answer 10

Dry ice is solid carbon dioxide. When it 'melts' it evaporates. There is no H2O in dry ice.