Estimate the total number of air molecules in a room capacity `25m^(3)` at a temperature of `27^(@)C` and 1 atm pressure.

Explanation

Given `V = 25m^(3)`,
`T = 273 + 27 = 30K`
`P = 1.013 xx 10^(5) Nm^(-2)`
`'mu = ?`
Applying `PV = muRT` we get
`'mu=(PV)/(RT)=(1.013xx10^(5)xx25)/(8.314xx300)`
`mu = 0.01015xx10^(5)` molecules
but 1 mole = `6.023 xx 10^(25)` moles.
Hence number of gaseous molecules present
`=0.01015xx10^(5)xx6.023xx10^(25)xx10^(25)=6.11xx10^(26).`