* Melting Gold: Melting gold simply changes its state from solid to liquid. The chemical composition of the gold remains the same. It's still gold (Au) with the same atomic structure.
* Pouring into a Mold: This changes the shape of the gold, but it's still the same material. No new substances are formed.
A chemical change would involve the gold reacting with something else to create a new substance. For example:
* Gold reacting with aqua regia: A mixture of nitric acid and hydrochloric acid can dissolve gold, forming gold ions. This is a chemical change because you are forming a new substance (gold ions).
In summary: Melting and pouring gold are physical changes because they don't alter the chemical composition of the gold.
