Question

9. (3 pts) The Spongebob Squarepants Macy's Thanksgiving parade balloon has a volume of 368 m3 The temperature for the parade is 45°F and the pressure is 0.987 atm, what mass of helium is in the balloon (in kg)?

Answer 1

Volume = 368 m³ = 368 × 1000 = 368000 dm^{3 =} 368000 L.

Temperature = 45⁰F

K - 273
=
45-32

Or, = 1.44

K - 273

Or, K = 280.3 K.

Pressure = 0.987 atm.

R = 0.082 L-atm/mol.K

Using ideal gas law

PV = nRT

Or, n = ( PV/RT)

Or, n = (0.987×368000)/(0.082×280.3) = 15800

Now, moles = ( mass/molar mass)

Molar mass of Helium = 4 g/mol.

Or, mass = molar mass × moles = ( 4× 15800 )

= 63210 g

= 63.21 Kg.