The approximate percentage composition of the atmosphere on four different planets is given in the table below.
The density of a gas may be defined as the mass of 1 dm3 of the gas measured at s.t.p. Which mixture of gases has the greatest density?
Planet major gases / % by no of molecules
A Jupiter H2 89.8 , He 10.2
B Neptune H2 80.0 , He 19.0, CH4 1.0
C Saturn H2 96.3 , He 3.25 , CH4 0.45
D Uranus H2 82.5 , He 15.2 . CH4 2.3
Density is proportional to the "average Mr of the mixture".
For example
A) 0.898 x 2 + 0.102 x 4 = 2.204
Repeat this for the 4 options and choose the largest result.