What do many bases have in common? apex chemistry sem 2

Define dew point. i am writing this part to be able to ask the question

What is the formula for the compound dinitrogen pentoxide? a. n4o5 b. n5o4 c. n4o6 d. n5o2 e. n2o5

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