How many grams of H3PO4 are in a 4 L sample of a 17 M solution?

Which type of fossil does this image depict?

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?

Under which circumstances are kp and kc equal for the reaction aa(g)+bb(g)⇌cc(g)+dd(g)?