What are specatator ions

About 3% of the water on earth is freshest. only about 40% of that freshwater is available for human use. why is so much freshwater unavailable for human use?

How do dying stars contribute to the formation of planets

4.25g sample of solid ammonium nitrate dissolves in 60.0g of water in a coffee-cup calorimeter, the temperature drops from 22.0 c to 16.9 c. assume that the specific heat of the solution is the same as that of pure water. calculate delta(h) (in kj/mol nh4no3) for the solution proces.