Final answer:
Boiling an egg is a chemical change due to changes in protein structure, which can't be reversed. Dry ice sublimating is a physical change as it's simply a state change not involving a chemical composition change.
Step-by-step explanation:
The processes of boiling an egg and dry ice sublimating to become a gas are examples of physical and chemical changes respectively. Boiling an egg is a chemical change because it involves a change in the composition of the egg's protein structure, which cannot be reversed. On the other hand, dry ice (which is solid carbon dioxide) sublimating, or turning directly from a solid to a gas, is a physical change because it only involves a change in state, not a change in the chemical composition of the substance.
Learn more about Physical and Chemical Changes