Helium is used to fill a balloon of diameter
56 cm at 26◦C and 1.9 atm.
The mass of a helium atom is 4.0026 u,
the conversion factor from u to kg is 1.66 × 10−27 kg/u, the conversion factor from atm to
Pa is 1.013 × 105 Pa/atm, the universal gas
constant 8.31451 J/Kmol, the Boltzmann’s