Final answer:
Breaking an egg is a physical change because it only involves a change in appearance or state, not in its chemical composition. Boiling an egg is a chemical change because it changes the egg's molecular structure in an irreversible way. These processes can be exothermic (releasing heat) or endothermic (absorbing heat).
Step-by-step explanation:
Breaking an egg is considered a physical change because it involves a change in the physical state or appearance of the egg without altering its fundamental composition. An example in the provided information is the heating of solid wax to form liquid wax, which is a physical change since it's the state of the matter that's altering, not the composition.
On the other hand, boiling an egg is a chemical change. When you boil an egg, it undergoes a chemical reaction that alters its fundamental molecular structure. This can be compared to the process of rusting: iron reacts with oxygen in the environment to form a new substance, rust. Boiling the egg changes the egg's proteins in a way that can't be reversed, making it a chemical change.
Moreover, these changes can be either exothermic or endothermic. In exothermic changes, heat is released, while in endothermic ones, heat is absorbed. The breaking of an egg is neither exothermic nor endothermic because it is simply a change in the physical state without any heat transfer. Boiling an egg is an endothermic process; it requires the absorption of heat to cook the egg.
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