Ninety-nine percent of all the matter that can be abserved in universe exists as?

What forms when chemical reactions combine pollution with sunlight?

Asample of freon gas has a volume of 2.23 liters, a pressure of 4.85 kpa, and a temperature of -1.36°c. calculate the volume at a pressure of 1.38 kpa and a temperature of 5.5°c. (show work)

Which sample at stp has the same number of atoms as 18 liters of ne at stp