Answer:
Bubbles and precipitates are both signs of a chemical change because they both indicate that a new substance has been formed.
Step-by-step explanation:
Bubbles and precipitates are both signs of a chemical change because they both indicate that a new substance has been formed.
Bubbles are formed when a gas is produced as a result of a chemical reaction. The formation of bubbles is a sign that a chemical change has occurred, as a new substance, the gas, has been created.
Precipitates, on the other hand, are solid particles that form when two or more liquids are mixed and a chemical reaction occurs. The formation of a precipitate is also a sign that a chemical change has occurred, as a new substance has been formed. The precipitate can be seen as a solid material that is visibly different from the original substances that were mixed.
In summary, both bubbles and precipitates are physical evidence that a chemical change has occurred because they both indicate that a new substance has been formed through a chemical reaction.