Compared to air, the density of an 80% He and 20% O₂mixture is about which of the following?

Question

Quizplus · Accepted Answer

The density of a gas mixture can be approximated by the average of its components' densities, weighted by their proportion in the mixture. Helium (He) is much less dense than air, while the "O₂" seems to be a typographical error and does not correspond to a known gas. Assuming it meant to refer to a gas denser than air (or simply a placeholder for the purpose of this question), the mixture would still be significantly lighter than air due to the large proportion of helium. Given helium's low density, a mixture of 80% helium and 20% of a denser gas would likely be closer to one-third the density of air, considering air's average density is around 1.225 kg/m³ at sea level and 15°C, and helium's density is about 0.1786 kg/m³ under the same conditions.

Compared to Air, the Density of an 80% He and 20