Sublimation of Dry Ice in a Closed System

In summary: If the walls are only 1 foot thick, the pressure buildup would be too much and the dry ice would not be able to sublimate.
  • #1
Inquirer18
2
0
Hello,

Please forgive my ignorance, although bright, I was a lousy student, & never took physics in school. I find it frustrating when relatives & friends are uncertain as to how to respond to questions like those below, so your educated reply would therefore be all the more appreciated. Thank you.

I would assume that frozen H20 completely filling the space of a closed system would convert to water if the container (one whose walls consisted of an energy conductor such as aluminum) would be placed in an environment above 0 Celsius, since extra room is not required for the newly formed water, as water is denser than ice. However, the converse, would probably not be true, as when placing the same container, this time filled completely with water in a room where the temperature is below 0 Celsius, since the water would have no room to expand when attempting to convert to a solid. Similarly, I would assume that dry ice completely filling a container, as the one described above, would not sublimate, when the container is placed in a room above -78.5 degrees Celsius. I understand that in the dry ice example, the container's walls would have to be sufficiently thick to offset the increasing pressure buildup resulting from sublimation. But if the inside of the container were, say, one square foot, and the walls of the container would be a foot thick, and instead of aluminum have the walls of the container made of titanium, would the dry ice sublimate without risk of explosion or would the pressure buildup not allow the dry ice to sublimate?
 
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  • #2
Inquirer18 said:
But if the inside of the container were, say, one square foot, and the walls of the container would be a foot thick, and instead of aluminum have the walls of the container made of titanium, would the dry ice sublimate without risk of explosion or would the pressure buildup not allow the dry ice to sublimate?

This would still rather depend on the strength of the walls and all that. A little difficult to say. Also, the boiling points of substances are measured at a known pressure. A liquid in a low pressure environment has a lower boiling point than when the liquid is at atmospheric pressure. Likewise, a liquid in a high pressure environment has a higher boiling point than when the liquid is at atmospheric pressure. The values you have are for atmospheric pressure, I think.
 
  • #3
All solids & liquids described above begin at atmospheric pressure. The question is does the temperature on the exterior of the container walls (namely the temperature in the room the container is situated in.) which is attempting to elevate the temperature of the dry ice within the container succeed in elevating the temperature within or does it not succeed? And if it does succeed is the dry ice able to sublimate or not? I wonder if the dry ice's temperature can only be elevated if it would be able to sublimate? In my example (if you'd prefer, we could talk about the walls being 100 feet thick. I don't really care how thick as long as they are sufficiently thick to NOT allow the pressure buildup to ever be able to cause the container to explode).
 

1. What is sublimation of dry ice in a closed system?

Sublimation is the process in which a solid, such as dry ice, changes directly into a gas without going through the liquid state. In a closed system, this occurs when the pressure and temperature reach a point where the solid and gas phases can coexist.

2. How does sublimation of dry ice in a closed system occur?

In a closed system, dry ice undergoes sublimation due to the decrease in pressure and increase in temperature. The decrease in pressure causes the solid carbon dioxide molecules to break apart and become a gas, while the increase in temperature provides the energy needed for the molecules to overcome their attractive forces and escape into the gas phase.

3. What factors affect the rate of sublimation of dry ice in a closed system?

The rate of sublimation in a closed system is affected by temperature, pressure, and the amount of surface area exposed to the dry ice. Higher temperatures and lower pressures will increase the rate of sublimation, while a larger surface area will result in a faster sublimation rate due to more molecules being exposed to the surrounding environment.

4. What are the potential hazards of sublimation of dry ice in a closed system?

The main hazard of sublimation in a closed system is the buildup of carbon dioxide gas, which can displace oxygen and lead to asphyxiation. This is a particular concern in enclosed or poorly ventilated spaces. Additionally, the rapid expansion of gas during sublimation can cause pressure buildup and potentially cause containers to burst.

5. How can sublimation of dry ice in a closed system be controlled or prevented?

To control or prevent sublimation in a closed system, it is important to ensure proper ventilation and monitoring of gas levels. Keeping the temperature and pressure stable can also help to slow down the rate of sublimation. Additionally, using insulated containers and handling dry ice with proper protective equipment can prevent accidents and injuries.

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