There's an AP chemistry problem that I vaguely remember. The problem showed four balloons, each with initially identical volumes, temperatures, and pressures. The balloons were filled with helium, oxygen, nitrogen, and xenon gases respectively. (This is entirely from memory, but the details aren't 100% relevant to where I'm going with this.)
The questions underneath the prompt and diagram then asked something about which...
- particles had the greatest average kinetic energy (they're the same because temp is proportional to average kinetic energy)
- particles had the fastest moving particles (helium because Graham's Law of Effusion says that the smallest particles - if all are at identical temperatures - move the fastest to make up for the lower mass)
- balloon had the greatest mass (xenon because they're at the same temp, pressure, and volume, so they have the same number of moles and xenon has the greatest molar mass)
- balloon would be expected to be the smallest after a day
It's that last one that's relevant to this video.
In the answer I remember, the helium balloon would be the smallest because its particles are the least massive, so they're moving the fastest at the same temperature. That means they'll randomly hit the microscopic holes in the balloon (all latex balloons have tiny holes we can't see with our naked eyes - imagine a rubber band ball inflated), so the helium would get out of the balloon the fastest (it would effuse through the tiny holes) leaving the helium balloon the smallest after some amount of time.
But it seems like xenon might be the correct answer for a much more complicated intermolecular force reason.
Vlad, I think I owe you a point retroactively.
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