Which of these substances is a compound

Carbon
Chlorine
Uranium
Ammonia

Substance x has a fixed volume, and the attraction between its particles is strong .substance y had widely spread out particles and can be compressed what can most likely be concluded about these substances

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

Sulfuric acid is a polyprotic acid. write balanced chemical equations for the sequence of reactions that sulfuric acid can undergo when it's dissolved in water.