Mass 0.14lbs volume 125 ml find the density in g/cm^3

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

A50.0 ml sample of gas at 20.0 atm of pressure is compressed to 40.0 atm of pressure at constant temperature. what is the new volume? 0.0100 ml 0.325 ml 25.0 ml 100. ml

An object resting on a table weighs 100 n. with what force is the object pushing on the table? with what force is the table pushing on the object? explain how you got your answer.