Question

Taking the composition of air to be `75%` of nitrogen and `25%` of oxygen by weight, calculate the velocity of sound through air.

Answer 1

The molecular weight of a mixture is given by
`(m_1+m_2+m_3)/(M)=(m_1)/(M_1)+(m_2)/(M_2)+(m_3)/(M_3)+`….
`(75+25)/(M)=(75)/(28)+(25)/(32)`
or `M=28.9g`
`c=sqrt(gamma(RT)/(M))=sqrt((1.4xx8.3xx1000xx273)/(28.9))=331.3(m)/(s)`
Here `gamma=1.4rarr` as both the gases are diatomic