Question

The KE of `N` molecule of `O_(2)` is `x` joules at `-123^(@)C`. Another sample of `O_(2)` at `27^(@)C` has a `KE` of `2x` joules. The latter sample contains
A. `N` molecules of `O_(2)`
B. `2N` molecules of `O_(2)`
C. `N//2` molecules of `O_(2)`
D. `N//4` molecules of `O_(2)`

Answer 1

Correct Answer - A
`KE= (3)/(2)RT, T= -123+273= + 150K`
`(3)/(2)xxRxx150= 3xx8.314xx75= xJ`
`=225xx 8.314=x`
At `27^(@)C= 27+223= 300K`
`KE` for `=2xJ=(3)/(2)xx8.314xx300`
`N` molecules
`:. x "Joule" =3xx8.314xx75`
In both the cases `x J` corresponds to `N` molecules.