SATP Chemistry 20 Help!?

[Krystal]

Three 1.0-L flasks contain He(g), N2(g), and H2S(g) at SATP. Which statement indicates the relative number of molecules in the flasks?

A.The flask of He(g) contains the most molecules.
B.The flask of N2(g) contains the most molecules.
C.The flask of H2S(g) contains the most molecules.
D.All three flasks contain the same number of molecules.

 

[jack]

D. All three flasks contain the same number of molecules.

same pressure same # molecules