A spherical balloon is made from a material whose mass is $3\mathrm{.}20$ kg $.$ The thickness of the material is negligible compared to the $1\mathrm{.}35$ m radius of the balloon. The balloon is filled with helium $($ He $)$ at a temperature of $315$ K and just floats in air, neither rising nor falling. The density of the surrounding air is $1\mathrm{.}19k\frac{g}{m^3}$ and the molar mass of helium is $4\mathrm{.}0026{10}^{-3}k\frac{g}{m}ol.$ Find the absolute pressure of the helium gas.

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$2.$ What is the average $($rms$)$ speed of the molecules of a helium gas at a temperature of $22C?\frac{m}{s}$