Question $9,$ chap $121,$ sect $1.$

part $1$ of $310$ points

Helium is used to fill a balloon of diameter $32$ cm at $20C$ and $0\mathrm{.}9$ atm $.$

The mass of a helium atom is $4\mathrm{.}0026$ u $,$ the universal gas constant id $8\mathrm{.}31451\frac{J}{K}$ mol, Boltzmann's constant is $1\mathrm{.}38066{10}^{-23}\frac{J}{K},$ and Avogadro's number is $6\mathrm{.}022{10}^{23}\frac{1}{m}ol.1\mathrm{.}66{10}^{-27}kg=1$ u $,$ and $101300Pa=1Pa.$

How many helium atoms are there in the balloon?

Question $10,$ chap $121,$ sect $1.$

part $2$ of $3,10$ points

What is the average kinetic energy of each helium atom?

Answer in units of J$.$