The average molecular speed is gretest in which of the following gas samples?

Options

A. `1.0 mol` of `O_(2)` at `560 K`
B. `0.50 mol` of `Ne` at `500K`
C. `0.20 mol` of `CO_(2)` at `440K`
D. `2.0 mol` of He at `140 K`

Answer

D

Explanation

Average molecular speed `= sqrt((8RT)/(pi M))` is dependent on T and M Thus, greater the value of `sqrt((T)/(M))`, the greater the molecular speed.
Thus, Gas `=sqrt((T)/(M)) implies O_(2)=sqrt((560)/(32))= 4.18`,
`Ne=sqrt((500)/(20))= 5.0`,
`CO_(2)=sqrt((440)/(44))= 3.16`
`He==sqrt(140)/(4)= 5.91`