Pick out the wrong statement.
The values of (∂P/∂V)T and (∂2P/∂V2)T are zero for a real gas at its critical point
Heat transferred is equal to the change in the enthalpy of the system, for a constant pressure, non-flow, mechanically reversible process
Thermal efficiency of a Carnot engine depends upon the properties of the working fluid besides the source & sink temperatures
During a reversible adiabatic process, the entropy of a substance remains constant
Correct Answer :
C. Thermal efficiency of a Carnot engine depends upon the properties of the working fluid besides the source & sink temperatures
Related Questions
When a gas is subjected to adiabatic expansion, it gets cooled due to
Decrease in velocity
Decrease in temperature
Decrease in kinetic energy
Energy spent in doing work
Grams of butane (C4H10) formed by the liquefaction of 448 litres of the gas (measured at (STP) would be
580
640
1160
Data insufficient; can't be computed
The effect of changing the evaporator temperature on COP as compared to that of changing the condenser temperature (in vapour compression refrigeration system) is
Less pronounced
More pronounced
Equal
Data insufficient, can't be predicted
Which is not a refrigerant?
SO2
NH3
CCl2F2
C2H4Cl2
In the equation, PVn = constant, if the value of n = ± ∞, then it represents a reversible __________ process.
Adiabatic
Isometric
Isentropic
Isothermal
COP of a refrigerator drawing 1 kW of power per ton of refrigeration is about
0.5
3.5
4.5
8.5
A gas can be liquefied by pressure alone only, when its temperature is __________ its critical temperature.
Less than
More than
Equal to or higher than
Less than or equal to
During Joule-Thomson expansion of gases
Enthalpy remains constant
Entropy remains constant
Temperature remains constant
None of these
A large iceberg melts at the base, but not at the top, because of the reason that
Ice at the base contains impurities which lowers its melting point
Due to the high pressure at the base, its melting point reduces
The iceberg remains in a warmer condition at the base
All (A), (B) and (C)
Which of the following is not an intensive property?
Molar heat capacity
Internal energy
Viscosity
None of these
The co-efficient of performance (COP) of a refrigerating system, which is its index of performance, is defined as the ratio of useful refrigeration to the net work. The units of __________ and COP are the same.
Kinematic viscosity
Work
Temperature
None of these
Pick out the correct statement:
In an isothermal system, irreversible work is more than reversible work
Under reversible conditions, the adiabatic work is less than isothermal work
Heat, work, enthalpy and entropy are all 'state functions'
Matter and energy cannot be exchanged with the surroundings in a closed system
For an ideal solution, the value of activity co-efficient is
0
1
< 1
> 1
Van Laar equation deals with the activity coefficients in
Binary solutions
Ternary solutions
Azeotropic mixture only
None of these
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
The thermodynamic law, PVy = constant, is not applicable in case of
Ideal compression of air
Free expansion of an ideal gas
Adiabatic expansion of steam in a turbine
Adiabatic compression of a perfect gas
The value of Cp & Cv respectively for monatomic gases in Kcal/kg Mole.°K are
5 & 3
3.987 & 1.987
1.987 & 0.66
0.66 & 1.987
For multi-component multiple phases to be in equilibrium at the same pressure and temperature, the __________ of each component must be same in all phases.
Chemical potential
Fugacity
Both (A) and (B)
Neither (A) nor (B)
The first law of thermodynamics is a restatement of the law of conservation of
Mass
Energy
Momentum
None of these
With increase in temperature, the atomic heat capacities of all solid elements
Increases
Decreases
Remains unchanged
Decreases linearly
A refrigerator may be termed as a
Heat pump
Heat engine
Carnot engine
None of these
The efficiency of an Otto engine compared to that of a diesel engine, for the same compression ratio will be
More
Less
Same
Data insufficient to predict
The energy of activation of exothermic reaction is
Zero
Negative
Very large compared to that for endothermic reaction
Not possible to predict
Gases are cooled in Joule-Thomson expansion, when it is __________ inversion temperature.
Below
At
Above
Either 'b' or 'c'
Isentropic process means a constant __________ process.
Enthalpy
Pressure
Entropy
None of these
The theoretical minimum work required to separate one mole of a liquid mixture at 1 atm, containing 50 mole % each of n- heptane and noctane into pure compounds each at 1 atm is
-2 RT ln 0.5
-RT ln 0.5
0.5 RT
2 RT
A refrigeration cycle is a reversed heat engine. Which of the following has the maximum value of the co-efficient of performance (COP) for a given refrigeration effect?
Vapor compression cycle using expansion valve
Air refrigeration cycle
Vapor compression cycle using expansion engine
Carnot refrigeration cycle
Pick out the wrong statement.
Activity co-efficient is dimensionless.
In case of an ideal gas, the fugacity is equal to its pressure.
In a mixture of ideal gases, the fugacity of a component is equal to the partial pressure of the component.
The fugacity co-efficient is zero for an ideal gas
In an ideal refrigeration cycle, the change in internal energy of the fluid is
+ve
-ve
0
Either of the above three; depends on the nature of refrigerant
Ideal refrigeration cycle is
Same as Carnot cycle
Same as reverse Carnot cycle
Dependent on the refrigerant's properties
The least efficient of all refrigeration processes