Chemistry
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A sealed flask containing 1.0 mole of H2(g) and a sealed flask containing 2.0
moles of He(g) are at the same temperature. The two gases must have equal
1. masses
2. volumes
3. average kinetic energies
4. numbers of molecules

I believe it is 4.

You haven't said anything about the volume of the containers or their pressures; therefore, I don't see how either 1 or 2 can be correct. The number of molecules certainly isn't correct since 2 moles He will contain twice as many molecules as 1 mole of H2.

the answer is 3