Dry ice is basically carbon dioxide in its solid-state. Due to its sublimable qualities and high melting point, it is used in shipping preserved items with low melting points such as meat, chocolates, ice-creams, etc. So, does dry ice melt? Dry ice does not melt at normal atmospheric pressure but undergo sublimation. Below -79 degrees Celsius and under 1 atmospheric pressure, it tends to transform into carbon dioxide gas. This is because carbon dioxide (CO2) can only exist in two states: solid and gas. To turn it into a liquid, it needs to be combined with another element resulting in a change in its chemical formula. Therefore, carbon combined with only oxygen to form carbon dioxide is stable in its solid and gaseous state. However, liquefied carbon dioxide is extracted from ammonia and hydrogen plants. But these also contain other compounds and can only be used for commercial purposes and not for laboratory experiments.
Why Does Dry Ice Not Melt?
Why Does Dry Ice Not Melt?
The melting properties of dry ice can easily be understood by understanding the term sublimation. To change the state of a compound, we need a particular temperature and pressure at the same time. The natural pressure present in our environment is equivalent to 1 atmosphere. It is interesting to note that carbon dioxide in normal atmospheric pressure of 1atm can only be stable in its gaseous and solid form. When it comes to liquid form, you need to combine it with another compound or increase the pressure. Therefore, if you want to create liquid carbon dioxide, it is only possible in laboratories.
The above carbon dioxide phase diagram shows that as the steepness of the slope rises, so does the likelihood of carbon dioxide melting. This is because a steeper slope increases pressure while maintaining the same temperature of -78 degrees Celsius. This exact condition is favorable for solid carbon dioxide or dry ice to melt. This state is only possible in laboratories inside pressure cans. To melt dry ice in its liquid form, you would be required to exert 5atmospheric pressure at -78 degrees Celsius.
How to Avoid Sublimation in Dry Ice?
How to Avoid Sublimation in Dry Ice?
Sublimation can be caused by the presence of heat. So, in the first place, you need to keep the dry ice away from heat. How to do that? An estimated amount of 5lbs is sublimated from dry ice within 24 hours. Unfortunately, you cannot stop it from sublimating, but you can definitely slow down the process.
Tips to Handle Dry Ice
Tips to Handle Dry Ice
Below are a few tips you can follow while handling dry ice:
Why is Dry Ice More Preferred Than Normal Ice?
Why is Dry Ice More Preferred Than Normal Ice?
The very property of dry ice to sublime instead of melting makes it a suitable fit in various instances.
Possible Hazards Due to Dry Ice
Possible Hazards Due to Dry Ice
Dry ice can act both as a friend and foe if not handled with care. However, before handling it, you must educate yourself about its properties and chemical reactions.
How To Understand Sublimation of Dry Ice?
How To Understand Sublimation of Dry Ice?
The easiest way to understand the sublimation of dry ice is the dry ice-water experiment. In this experiment, you need to put a piece of dry ice into warm water. Warm water will change the temperature of the dry ice, and it will start to sublime. Soon, bubbles would start forming near the ice. This bubble contains no water. As a result, water will evaporate and go inside the CO2 bubbles. Due to the low temperature of CO2 bubbles, water would condense into tiny droplets. This equation will follow Le Chatelier’s principle. And thus, their droplets would take the shape of a cloud. With the visible cloud, the process of sublimation is dry ice can be observed clearly.
Conclusion
Dry ice is a very interesting compound to play with. Along with the properties of Co2, many fun experiments are possible with dry ice. From the above article, now you must have got the idea about how to melt a piece of dry ice and if it is possible under atmospheric pressure. But, unfortunately, liquid carbon dioxide is not purely used in commercial products, and even if it is used, they only utilize it to make dry ice out of it. Always have your lab instructor with you while handling dry ice since it can cause severe health hazards if not handled well. Follow all the instructions before performing any experiments with it, especially if you wish to melt it into liquid. The glass beaker has a chance to explode if handled casually. Thus, take necessary actions.
