Question

A gas `(C_(v.m) = (5)/(2)R)` behaving ideally is allowed to expand reversibly and adiabatically from `1` litre to `32` litre. Its initial temperature is `327^(@)C`. The molar enthalpy change (in `J//mol`) for the process is :
A. `-1125 R`
B. `-625 R`
C. `-1575 R`
D. None of these

Answer 1

Correct Answer - C
`(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`