In which main energy level does the 's' sublevel first appear? k (first main energy level) l (second main energy level) m (third main energy level) n (fourth main energy level)

hi,

the answer is d.indefinite shape but definite volume, let go oogle u out

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the reaction mixture contains some ammonia, plus a lot of unreacted nitrogen and hydrogen. the mixture is cooled and compressed, causing the ammonia gas to condense into a liquid. the liquefied ammonia is separated and removed. the unreacted nitrogen and hydrogen are then recycled back into the reactor .