Pick out the correct statement.
Entropy and enthalpy are path functions
In a closed system, the energy can be exchanged with the surrounding, while matter cannot be exchanged
All the natural processes are reversible in nature
Work is a state function
Correct Answer :
C. All the natural processes are reversible in nature
Related Questions
The temperature at which a real gas obeys the ideal gas laws over a wide range of pressure is called the __________ temperature.
Critical
Boyle
Inversion
Reduced
In a turbine, the fluid expands almost
Isothermally
Isobarically
Adiabatically
None of these
Generation of heat by friction is an example of a/an __________ change.
Isothermal
Irreversible
Adiabatic
Reversible
A domestic refrigerator has a/an __________ cooled condenser.
Water
Air
Evaporative
Gas
Heat pump
Accomplishes only space heating in winter
Accomplishes only space cooling in summer
Accomplishes both (A) and (B)
Works on Carnot cycle
The expression for entropy change, ΔS = n Cp . ln (T2/T1), is valid for the __________ of a substance.
Simultaneous pressure & temperature change
Heating
Cooling
Both (B) and (C)
The change in __________ is equal to the reversible work for compression in steady state flow process under isothermal condition.
Internal energy
Enthalpy
Gibbs free energy
Helmholtz free energy
All gases during throttling process at atmospheric temperature and pressure show a cooling effect except
CO2
H2
O2
N2
Normal temperature and pressure (N.T.P.) corresponds to
0°C and 760 mm Hg
15°C and 760 mm Hg
20°C and 760 mm Hg
0°C and 1 kgf/cm2
The quantitative effect of temperature on chemical equilibrium is given by the
Vant-Hoff equation
Le-Chatelier's principle
Arrhenius equation
None of these
__________ increases with increase in pressure.
The melting point of wax
The boiling point of a liquid
Both (A) and (B)
Neither (A) nor (B)
Adiabatic compression of a saturated water vapour makes it
Supersaturated
Superheated
Both (A) and (B)
Neither (A) nor (B)
Free energy, fugacity and activity co-efficient are all affected by change in the temperature. The fugacity co-efficient of a gas at constant pressure ____with the increase of reduced temperature.
Decreases
Increases
Remains constant
Decreases logarithmically
Which of the following is a widely used refrigerant in vapour compression refrigeration system (using large centrifugal compressor)?
Freon
Liquid sulphur dioxide
Methyl chloride
Ammonia
Fugacity and pressure are numerically equal, when the gas is
In standard state
At high pressure
At low temperature
In ideal state
The molar excess Gibbs free energy, gE, for a binary liquid mixture at T and P is given by, (gE/RT) = A . x1. x2, where A is a constant. The corresponding equation for ln y1, where y1 is the activity co-efficient of component 1, is
A . x22
Ax1
Ax2
Ax12
A change in state involving a decrease in entropy can be spontaneous, only if
It is exothermic
It is isenthalpic
It takes place isothermally
It takes place at constant volume
Gibbs-Duhem equation relates composition in liquid phase and the __________ at constant temperature & pressure.
Fugacity
Partial pressure
Activity co-efficient
All (A), (B), and (C)
Cp - Cv = R is valid for __________ gases.
Ideal
Very high pressure
Very low temperature
All of the above
The partial molar enthalpy of a component in an ideal binary gas mixture of composition Z, at a temperature T and pressure P, is a function only of
T
T and P
T, P and Z
T and Z
COP of a refrigerator drawing 1 kW of power per ton of refrigeration is about
0.5
3.5
4.5
8.5
One ton of refrigeration is defined as the heat rate corresponding to melting of one ton of ice in one
Hour
Day
Minute
Second
In which of the following reaction equilibrium, the value of equilibrium constant Kp will be more than is Kc?
2HI H2 + I2
N2O4 2NO2
2SO2 + O2 2SO3
None of these
Henry's law is closely obeyed by a gas, when its __________ is extremely high.
Pressure
Solubility
Temperature
None of these
Linde gas liquefaction process employs cooling
By throttling
By expansion in an engine
At constant pressure
None of these
In a P-V diagram (for an ideal gas), an isothermal curve will coincide within adiabatic curve (through a point), when
Cp < Cv
Cp = Cv
Cp > Cv
C ≥ Cv
The most important application of distribution law is in
Evaporation
Liquid extraction
Drying
Distillation
Entropy change for an irreversible isolated system is
∞
0
< 0
> 0
In reactions involving solids and liquids (where change in volume is negligible), the heat of reaction at constant pressure as compared to that at constant volume is
More
Less
Same
Unpredictable; depends on the particular reaction
The freezing point of a liquid decreases when the pressure is increased, if the liquid __________ while freezing.
Contracts
Expands
Does not change in volume
Either (A), (B) or (C)