Help me pretty pls this is confusing

Which substance absorbs 58.16 kj of energy when 3.11 mol vaporizes? a)ch4 b)h2s c)co2 d)nacl

Which term best describes the form sound takes as it travels away from a drum (a- gas)(b-music) ( c-waves) (d-particles

11. phosphorus-32 is radioactive and has a half life of 14 days. how much of a 124 mg sample of phosphorus-32 is present after 56 days? a) 7.75 mg b) 15.5 mg c) 31.0 mg d) 62.0 mg