Answer:
- The "piece 3: The solid fizzes when acid is dropped on the surface", indicates a chemical change
Step-by-step explanation:
- The question is: Which piece, when treated, indicates a chemical change?
Solution
A chemical change is only manifested when a chemical reaction occurs, which means that the original substance is transformed into one or more different substances. In a chemical change either the original substance decomposes (by action of the heat, light or other influence) or combines with other substances, becoming a new substance.
Piece 1: The solid is hammered into a flat sheet.
In this case the silver has not been transformed into a different substance; it has only changed its shape. Thus, this is just a physical change.
Piece 2: The solid is heated in a flame until it melts.
Again, the final substance is still silver. It has only suffered a change of state. Thus, this is a physical change too.
Piece 3: The solid fizzes when acid is dropped on the surface.
Fizzing is a sign that a new substance has formed. In this case, the acid reacted with the piece of silver, forming a compound of silver and a gas (likey hydrogen).
Typically metals react with acids forming a salt ans hydrogen gas.
Piece 4: The solid is place in a beaker of water and it floats.
The silver has not suffered any change.