Three moles of oxygen ar mixed with two moles of helium. What will be the ratio of specific heats at constant pressure and constant volume for the mixture ?

Options

A. 1.2
B. 1.5
C. 2
D. 1.8

Answer

B

Explanation

Oxygen is diatomic. Hence `gamma_(0)=7/5`
and Helium is monoatomic. `" "thereforegamma_(He)=5/3`
The gases are mixed and to find `gamma`, we take their weighted average.
`thereforegamma` for the mixture = `(3gamma_(0)+2gamma_(He))/((3+2))`
`=(3xx7/5+2xx5/3)/5`
`=(21/5+10/3)/5`
`=(63+50)/(15xx5)=113/75=1.5`