Rank the gases Ar, N2 , CH4 , and C2 H6 in order of increasing density at STP.

a) CH4 2H6 < N2 < Ar

b) CH4 < N2 < Ar < C2H6

c) Ar < C2H6 < N2 < CH4

d) CH4 < N2 < C2H6 < Ar

Solution 15SAQ Step 1: Derive the equation for density using the ideal gas equation. Step 2: As shown in the derived equation, since pressure and temperature are the same for all gases, the molar mass will be the basis for determining the order in terms of increasing density of the gases. Since there is direct proportionality between molar mass and the density, this means the higher the molar mass, the denser is the gas.