How many grams of oxygen are in 4.5 moles of hno3

Write the empirical chemical formula of calcium with a mass percent of 38.8, phosphorus with a mass percent of 20.0, and oxygen with a mass percent of 41.3.

How are evaporation and sublimation similar? a both involve the formation of a gas. b both release energy to the surroundings. c both take place throughout a solid. d both take place at the surface of a liquid.

Elements in group 2 are all called alkaline earth metals. what is most similar about the alkaline earth metals?