What is sublimation? Cite a common example of sublimation.

Understanding the concept of phase transition is critical in the study of matter and its properties. Phase transition refers to the process of changing from one state of matter to another, commonly occurring among the three classical states: solid, liquid, and gas. In the context of our discussion, sublimation is a specific type of phase transition where a substance converts from a solid directly into a gas.

During this process, energy is either absorbed or released. This energy is known as latent heat and it applies to all phase transitions. In sublimation, latent heat is absorbed by the solid as it transforms into gas, which is why this process is endothermic. Let's visualize this with dry ice. When it's exposed to room temperature, the heat from the surroundings is absorbed by the dry ice causing it to transition into carbon dioxide gas without becoming liquid first.

The transition from solid to gas, or sublimation, can be quite fascinating to observe. Not all substances go through this transition under normal conditions. For sublimation to occur, substances must possess specific physical characteristics and be under particular environmental conditions, including low atmospheric pressure or high temperature.

For example, snow and ice can sublimate during the winter, which can result in the phenomenon known as 'snow disappearances' without leaving any puddles. This seemingly 'magical' transformation is simply a scientific process where molecular energy overcomes molecular forces of attraction so rapidly that substances skip the liquid phase entirely.

Dry ice is one of the most known examples of sublimation in action and serves as an excellent educational tool. It is the solid form of carbon dioxide (CO2), which sublimates at a temperature of -78.5 degrees Celsius (-109.3 degrees Fahrenheit) at standard atmospheric pressure.

Due to its low temperature, dry ice is extremely useful as a refrigerant to preserve frozen foods during transportation, as it keeps them cold longer without leaving liquid residue that would result from melting. The fog-like smoke produced during sublimation also creates visual effects often used in theatrical productions and parties.

Lastly, let's delve into physical chemistry, the branch of chemistry focused on studying how matter behaves on a molecular and atomic level and how chemical reactions occur. Understanding sublimation ties into this field as it involves a deep look at both thermodynamics and kinetics.

Physical chemistry explains why and how substances like dry ice can skip the liquid state during phase changes. It involves calculations of energy changes, study of matter's properties under different conditions, and how these properties relate to the chemical bonds and structure of a substance. The fascinating sublimation of dry ice is just one of the myriad phenomena explained within this substantial and exciting field.