What is an ion?                           
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Agas can holds 2.0 gal of gasoline. what is this quantity in cubic centimeters?

In a laboratory, 1.55mg of an organic compound containing carbon, hydrogen, and oxygen is burned for analysis. this combustion resulted in the formation of 1.45mg of carbon dioxide and .89 mg of water. what is the empirical formula for this compound?

How many moles is 14.5 cm^3 of platinum? the density of platinum is 21.45 g/cm^3.