In 1988, three gray whales were trapped in Arctic ice. Television crews captured the frantic attempts of hundreds of people to save the whales. Eventually, a Soviet icebreaker and U. S. National Guard helicopters arrived to help free the whales. The cost of the rescue mission exceeded $5 million. Write in a scientific question?

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.)

Compare and contrast physical changes with chemical changes.

This chart lists four kinds of polymers and their sources. what can be known about all four polymers, despite their differences? they come from living things. they share ionic carbon bonds. they are at least 100 monomers long. they are made of repeating subunits.