Which element could fill in as the X in the compound formula XH2, based on the elements & their charges by group on the periodic table?
A. Cl
B. P
C. C
D. S

Great amounts of electromagnetic energy from our sun and other bodies in space travel through space. which is a logical conclusion about these electromagnetic waves? their energy must be very their frequency must be very low these waves can travel without a medium they only travel through a vacuum of space

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?

If 3 moles of a compound use 24 j of energy in a reaction, what is the a hreaction in j/mol?