Conservation of entropy -- adiabatic process

[AlexS]

Hello.I have a question about entropy of a thermodynamic system.
1)If we have let say a gas that is separated by some thermo isolated walls (so no heat goes in or out) does the entropy of that gas conserve? I taught that if S=dQ/dt, because Q=0,then the entropy should be conserved.
2)So,does the entropy of a system that undergoes an adiabatic process conserve?

 

[Chestermiller]

No. Entropy is generated in a system experiencing an adiabatic irreversible process and is constant in a system experiencing and adiabatic reversible process. Entropy is not a quantity that,in general, is conserved.