This is percent yield I’m confused

How many moles of air are there in a human lung with a volume of 2.4 l at stp? explain your answer

Which class of molecules functions as chemical signals? hormones water carbohydrates proteins

Apump contains 0.5 l of air at 203 kpa.you draw back on the piston of the pump, expanding the volume until the pressure reads 50.8 kpa. what is the new volume of the air pump