A gas `(C_(v,m)=(5)/(2)R)` behaving ideally was allowed to expand reversibly and adiabatically from 1 litre to 32 litre. Its initial temperature was `327^(@)C`. The molar enthalpy change (in J/mol) for the process is:

Options

A. `-1125 R`
B. `-625 R`
C. `-1575 R`
D. None of these

Answer

C

Explanation

`(T_(2))/(T_(1)) = ((V_(1))/(V_(2)))^(gamma-1)`
or `T_(2) = 150 K`
`DeltaH_(m) = nC_(P)DeltaT = (7)/(2)R(150 - 600) = -1575 R`