During a reversible isothermal expansion of an ideal gas, the entropy change is___________________?

A. Heating takes place
B. Cooling takes place
C. Pressure is constant
D. Temperature is constant

A. Isothermal compression
B. Isothermal expansion
C. Adiabatic expansion
D. Adiabatic compression

A. It should be non-explosive
B. It should have a sub-atmospheric vapor pressure at the temperature in refrigerator coils
C. Its vapor pressure at the condenser temperature should be very high
D. None of these

A. (∂T/∂V)S, ni = -(∂P/∂S)V, ni
B. (∂S/∂P)T, ni = (∂V/∂T)P, ni
C. (∂S/∂V)T, ni = (∂P/∂T)V, ni
D. (∂T/∂P)S, ni = (∂V/∂S)P, ni

A. Pressure must be kept below 5.2 atm
B. Temperature must be kept above – 57°C
C. Pressure must be kept below 5.2 atm. and temperature must be kept above 57°C
D. Pressure and temperature must be kept below 5.2 atm. and – 57°C respectively

A. He
B. N2
C. O2
D. H2