Final answer:
When water is boiled, it undergoes a physical change from liquid to gas by breaking hydrogen bonds, a process based on physical properties. However, boiling an egg causes a chemical change in the proteins, making the liquid egg white solidify due to the formation of new bonds and aggregation of protein molecules.
Step-by-step explanation:
The phenomenon of a liquid turning into a gas when it boils compared to an egg turning from liquid to solid when boiled can be explained by the nature of the substances and the processes involved. For liquids like water, boiling corresponds to the phase transition from liquid to gas. The key change here involves the breaking of hydrogen bonds between water molecules, allowing them to escape as steam or vapor due to increased kinetic energy.
Conversely, when an egg is boiled, we are observing a chemical change within the proteins of the egg, particularly albumin. Heat application causes these protein molecules to unfold, breaking the existing hydrogen bonds, thus forming a disorganized solid as the proteins coagulate. This process is spontaneous and irreversible at temperatures above 373 K.
Therefore, while boiling water is a physical change resulting in a phase transition without altering chemical structure, boiling an egg induces a chemical change that changes the structure of the proteins, resulting in a solid mass.