Changing colors is not an indication of a chemical change.

Silver tarnishes as silver metal reacts with hydrogen sulfide, h2s, in the air. in this reaction, dark silver sulfide, au2s, covers the surface of silver. when silver is polished, this coating of silver sulfide can be removed from the surface. this makes the silver shiny again. enter the coefficients that balance the tarnishing reaction equation. (type 1 for no coefficient.)

An observation that requires measurement is called quantitative observable or qualitative

The tendency of water molecules to stick together is referred to as a) adhesion b) polarity c) cohesion d) transpiration e) evaporation