Question

Five moles of helium are mixed with two moles of hydrogen to form a mixture. Take molar mass of helium $M_1=4g$ and that of hydrogen $M_2=2g$
The equivalent value of $\gamma$ is ............(as nearest integer)

Answer 1

Value of $\gamma$ for He (monoatomic) is (5/2) and for hydrogen gas (diatomic) is (7/2).
So equivalent value of $\gamma$ is $\frac{\sum n_i{\gamma }_i}{\sum n_i}=\frac{\sum 5\times 5/2+2\times 7/2}{\sum 5+2}=\frac{39}{14}$.