Two samples of carbon come into contact. A heat transfer will occur between sample A and sample B. What must be true for heat to transfer from sample A to sample B?

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.)

Many ionic compounds and a few highly polar covalent compounds are because they completely ionize in water to create a solution filled with charged ions that can conduct an electric current.

Air can be considered a mixture. which statement does not explain why?