5.17 Calculate the volume occupied by 8.8 g of CO2 at 31.1°C and 1 bar pressure.
R = 0.083 bar L K
–1 mol–1.


Given,
Radius of the balloon = r = 10 m
Volume of the balloon = = 43 πr3
 
= 43 × 227 × 103
 = 4190.5 m3 ( approx )

Thus, the volume of the displaced air is 4190.5 m3
Given,
Density of air = 1.2 kg m-3
Then, mass of displaced air = 4190.5 × 1.2 kg
                                              = 5028.6 kg
Now, mass of the helium (m) inside the balloon is given by,


 m = MpVRT
 Here, 
  M = 4 × 10-3 kgmol-1
  p = 1.66 bar
 V = Volume of the balloon
     = 4190.5 m3
 R = 0.083 bar dm3 K-1mol-1
 T = 27°C = 300 K

 Then, m = 4×10-3×1.66×4190.5×1030.083×300
                = 1117.5kg (approx)
Now, total mass of the balloon filled with helium = (100 + 1117.5) kg
                                                                             = 1217.5 kg
Hence, pay load = (5028.6 – 1217.5) kg
                           = 3811.1 kg
Hence, the pay load of the balloon is 3811.1 kg.