Question

10 g of neon initially at a pressure of 506.625 kPa and temperature of 473 K expand adiabatically to a pressure of 202.65 kPa. Calculate entropy change of the system and total entropy change for the following ways of carrying out this expansion. Expansion is carried out reversibly

• A. $\Delta S_{sys}=0;\Delta S_{surr}=0$ and $\Delta S_{total}=0$
• B. $\Delta S_{sys}=1.03;\Delta S_{surr}=-1.03$ and $\Delta S_{total}=0$
• C. $\Delta S_{sys}=-3.2;\Delta S_{surr}=3.2$ and $\Delta S_{total}=0$
• D. None of these

Answer 1

The correct option is A $\Delta S_{sys}=0;\Delta S_{surr}=0$ and $\Delta S_{total}=0$

For reversible process, dS = dQ/T

For adiabatic process, Q=0

Hence, $\Delta S=0$

$\Delta S_{sys.}=0,\Delta S_{surr.}=0,\Delta S_T=0$