20. What is an irreversible change?
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Calculate the mass of silver needed to react with chlorine to produce 126g if silver chloride?

Which statement correctly describes metallic bonds? a. they form when certain atoms lose electrons and other atoms gain electrons. b. they involve an attraction between anions and cations. they always involvpoth a metal and a nonmetal. d. they can only form between atoms of the same element. e. they form because electrons can move freely between atoms.

Chen drew a diagram to compare the ways in which different organisms obtain nitrogen. which label belongs to the area marked z?