Estimate the speed of sound in air at standard temperature and pressure. The mass of 1 mole of air is `29.0 xx 10^(-3) kg`.

Explanation

We know that 1 mole of any gas occupies 22.4 litres at STP. Therefore, density of air at STP is :
`rho_(o) = ("mass of mole of air")// ("volume of one mole of air at STP")`
`= (29.0 xx 10^(-3) kg)/(22.4 xx 10^(-3) m^(3))`
`= 1.29 kg m^(-3)`
According to Newton.s formula for the speed of sound in a medium, we get for the speed of sound in air at STP,
`v = [(1.01 xx 10^(5) N m^(-2))/(1/29 kg m^(-3))]^(1//2) = 280 m s^(-1)` (15.23)