Final answer:
When gold is melted to make jewelry, a physical change occurs as the chemical composition of gold remains unchanged, only its form is altered. This change is reversible, and the physical appearance of gold can change without affecting its elemental nature.
Step-by-step explanation:
When gold is melted and formed in a mold to make a piece of jewelry, the type of change taking place is a physical change. Melting solid gold into liquid gold does not alter its chemical structure; it merely changes its physical form. This process is analogous to melting ice into water; the molecular composition of H2O remains the same, though its physical state changes.
This is true for any pure substance that changes phase; such transformations are considered physical changes because no new substance is produced and the chemical nature of the material remains the same. In the case of gold jewelry making, it can be hammered, melted, or cast, yet it continues to be elemental gold. Physical changes are generally reversible, and melting is a classic example, where the melted gold can solidify back into solid gold upon cooling.