Walter and Luis Alvarez hypothesized that an asteroid impact caused the formation of a 66- million-year-old layer of clay containing high levels of iridium. How did geologists test this hypothesis? What evidence did they look for?

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.)