Four cylinders filled with gas are at the same temperature. In which of the following will the gas exert the most pressure?
A) A 2.0 L cylinder containing 4.0 g of H2.
B) A 2.0 L cylinder containing 4.0 g of He.
C) A 1.0 L cylinder containing 16.0 g of O2
D) None. At constant temperature, pressure is constant.
*I understand that when volume decreases, pressure increases but that is about all I know. Here it involves mass, molar mass and volumes and I don't know how to relate that to the basic knowledge I have that I just mentioned (volume decreases when pressure increases).