Answer:
Explanation:
According to Avogadro's principle, equal volume of gases at the same temperature and pressure will contain the same number of particles (atoms or molecules).
Therefore, being the three flasks identical, which includes that they have the same volumen, and being that they contain different gases at standard temperature and pressure, regardless of the chemical formula of each gas, by direct use of Avogadro's principle, they all will contain the same number of molecules.
The ideal gas equation, pV = nRT reflects this fact: if you isolate the ratio V/n, you get V/n = RT/p. Then, since RT/p (the right side) is constant, V/n is also constant, meaning that for a fixed volume the number of particles is constant, regardelss of the gas.