Silver tarnishes and turns black/black--do you think it is a physical change or a chemical change?
Answer:
since it tarnishes by exposure to air, this changes its chemical structure , so it is considered as a chemical change.
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"Why silver turns black"
It changes color either because it gets dirty, or because the silver or impurities in the silver are oxidized by the air around it (which is a chemical change).
Edit to note that "oxidized" is a chemical reaction term, not necessarily involving oxygen, rather a loss of electrons. In this case it is normally sulfur or hydrogen forming bonds with the silver that oxidizes it and turns it black.
The tarnish you see on silver is silver sulfide; it forms from the silver reacting from small amounts of hydrogen sulfide in the air. This is a chemical change, because the silver has reacted with something to form a different material. A physical change is like melting, freezing, vaporizing, or grinding to powder, where it is still the same material as you started with, only the form has been changed.
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