The correct response is:
the mass of each gas
Explanation:
At the same pressure, volume, and temperature, the two gases are in the same physical conditions, but they can have different identities, which means their masses can differ. The number of moles is determined by the Ideal Gas Law \( PV = nRT \), therefore if the pressure, volume, and temperature are the same, the number of moles of each gas will also be the same. The molar volume is a property related to the conditions under which the gas is measured, which remains consistent under these conditions for different gases. The gas constant is specific to the Ideal Gas Law and does not differ between different gases; it is a universal constant.
4 answers