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
Correct Answer :
C. Gibbs free energy
Related Questions
Lenz's law results from the law of conservation of
Mass
Momentum
Energy
None of these
Heating of water under atmospheric pressure is an __________ process.
Isochoric
Isobaric
Adiabatic
Isothermal
Air enters an adiabatic compressor at 300K. The exit temperature for a compression ratio of 3, assuming air to be an ideal gas (Y = Cp/Cv = 7/5) and the process to be reversible, is
300 × (32/7)
300 × (33/5)
300 × (333/7)
300 × (35/7)
The ratio of equilibrium constants (Kp2/Kp1) at two different temperatures is given by
(R/ΔH) (1/T1 - 1/T2)
(ΔH/R) (1/T1 - 1/T2)
(ΔH/R) (1/T2 - 1/T1)
(1/R) (1/T1 - 1/T2)
The expression, nRT ln(P1/P2), is for the __________of an ideal gas.
Compressibility
Work done under adiabatic condition
Work done under isothermal condition
Co-efficient of thermal expansion
The temperature at the eutectic point of the system is the __________ temperature that can be attained in the system.
Lowest
Highest
Average
None of these
In vapour compression refrigeration system, if the evaporator temperature and the condenser temperatures are -13°C and 37°C respectively, the Carnot COP will be
5.2
6.2
0.168
Data insufficient, can't be found out
The standard state of a gas (at a given temperature) is the state in which fugacity is equal to
Unity
Activity
Both (A) & (B)
Neither (A) nor (B)
If the heat of solution of an ideal gas in a liquid is negative, then its solubility at a given partial pressure varies with the temperature as
Solubility increases as temperature increases
Solubility increases as temperature decreases
Solubility is independent of temperature
Solubility increases or decreases with temperature depending on the Gibbs free energy change of solution
The internal energy of an ideal gas does not change in a reversible __________ process.
Isothermal
Adiabatic
Isobaric
Isometric
Gibbs free energy of a pure fluid approaches __________ as the pressure tends to zero at constant temperature.
Infinity
Minus infinity
Zero
None of these
For an isothermal process, the internal energy of a gas
Increases
Decreases
Remains unchanged
Data insufficient, can't be predicted
Pick out the wrong statement.
At constant pressure, solubility of a gas in a liquid diminishes with rise in temperature
Normally, the gases which are easily liquefied are more soluble in common solvents
The gases which are capable of forming ions in aqueous solution are much more soluble in water than in other solvents
At constant pressure, solubility of a gas in a liquid increases with rise in temperature
Pick out the wrong statement.
Minimum number of degree of freedom of a system is zero
Degree of freedom of a system containing a gaseous mixture of helium, carbon dioxide and hydrogen is 4
For a two phase system in equilibrium made up of four non-reacting chemical species, the number of degrees of freedom is 4
Enthalpy and internal energy change is zero during phase change processes like melting, vaporisation and sublimation
Number of degrees of freedom for a three phase system in equilibrium comprising of three nonreacting chemical species is
2
0
1
3
As the temperature is lowered towards the absolute zero, the value of ∂(ΔF)/∂T, then approaches
Unity
Zero
That of the heat of reaction
Infinity
For a constant volume process __________ by the system is used only to increase the internal energy.
Heat absorbed
Work done
Both (A) & (B)
Neither (A) nor (B)
The first law of thermodynamics is a statement of conservation of
Heat
Momentum
Energy
Work
Steam undergoes isentropic expansion in a turbine from 5000 kPa and 400°C (entropy = 6.65 kJ/kg K) to 150 kPa) (entropy of saturated liquid = 1.4336 kJ/kg. K, entropy of saturated vapour = 7.2234 kJ/kg. K) The exit condition of steam is
Superheated vapour
Partially condensed vapour with quality of 0.9
Saturated vapour
Partially condensed vapour with quality of 0.1
Vapour which is at a pressure smaller than the saturation pressure for the temperature involved is called a __________ vapour.
Superheated
Desuperheated
Non-condensable
None of these
Which of the following is not affected by temperature changes?
Fugacity
Activity co-efficient
Free energy
None of these
The equation, PV = nRT, is best obeyed by gases at
Low pressure & high temperature
High pressure & low temperature
Low pressure & low temperature
None of these
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
Measurement of thermodynamic property of temperature is facilitated by __________ law of thermodynamics.
1st
Zeroth
3rd
None of these
Pick out the wrong statement pertaining to the decomposition of PCl5 represented by, PCl5 PCl3 + Cl2.Degree of dissociation of PCl5 will
Decrease on addition of Cl2
Increase on addition of an inert gas at constant pressure
Decrease on increasing the pressure of the system
None of these
At the absolute zero temperature, the entropy of every perfectly crystalline substance becomes zero. This follows from the
Third law of thermodynamics
Second law of thermodynamics
Nernst heat theorem
Maxwell's relations
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)
Out of the following refrigeration cycles, which one has the minimum COP (Co-efficient of performance)?
Air cycle
Carnot cycle
Ordinary vapour compression cycle
Vapour compression with a reversible expansion engine
Which of the following is not a common refrigerant?
Freon-12
Ethylene
Ammonia
Carbon dioxide
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