All gases except __________ shows a cooling effect during throttling process at atmospheric temperature and pressure.
Oxygen
Nitrogen
Air
Hydrogen
Correct Answer :
D. Hydrogen
Related Questions
Melting of wax is accompanied with __________ in entropy.
Increase
Decrease
No change
None of these
In a homogeneous solution, the fugacity of a component depends upon the
Pressure
Composition
Temperature
All (A), (B) and (C)
When a system is in equilibrium for all possible processes, the differential or finite change of entropy is
< 0
> 0
= 0
None of these
Pick out the correct statement.
Compression ratio of an Otto engine is comparatively higher than a diesel engine
Efficiency of an Otto engine is higher than that of a diesel engine for the same compression ratio
Otto engine efficiency decreases with the rise in compression ratio, due to decrease in work produced per quantity of heat
Diesel engine normally operates at lower compression ratio than an Otto engine for an equal output of work
The equation, Cp - Cv = R, is true for __________ gas.
No
Any real
Only ideal
Both (B) and (C)
The enthalpy change when ammonia gas is dissolved in water is called the heat of
Solution
Formation
Dilution
Combustion
On a P-V diagram of an ideal gas, suppose a reversible adiabatic line intersects a reversible isothermal line at point A. Then at a point A, the slope of the reversible adiabatic line (∂P/∂V)s and the slope of the reversible isothermal line (∂P/ ∂V)T are related as (where, y = Cp/Cv)
(∂P/∂V)S = (∂P/∂V)T
(∂P/∂V)S = [(∂P/∂V)T]Y
(∂P/∂V)S = y(∂P/∂V)T
(∂P/∂V)S = 1/y(∂P/∂V)T
In the equation PVn = constant, if the value of n = y = Cp/Cv, then it represents a reversible __________ process.
Isothermal
Adiabatic
Isentropic
Polytropic
Cv for an ideal gas
Does not depend upon temperature
Is independent of pressure only
Is independent of volume only
Is independent of both pressure and volume
The free energy change for a chemical reaction is given by (where, K = equilibrium constant)
RT ln K
-RT ln K
-R ln K
T ln K
At normal boiling point, molar entropy of vaporisation is __________ Joule/K°.mole.
72
92
142
192
For a cyclic process, a fixed ratio between heat and work
Always exists
May exist
Never exists
Is difficult to predict
The equation relating E, P, V and T which is true for all substances under all conditions is given by (∂E/∂V)T = T(∂P/∂T)H - P. This equation is called the
Maxwell's equation
Thermodynamic equation of state
Equation of state
Redlich-Kwong equation of state
In a reversible process
Tds = dE + dW
dE - dW = Tds
dW - dE = Tds
Tds - dW + dE >0
In jet refrigerators, the refrigerating fluid is practically always
Water
Ammonia
Freon
Brine
Which of the following identities can be most easily used to verify steam table data for superheated steam?
(∂T/∂V)S = (∂p/∂S)V
(∂T/∂P)S = (∂V/∂S)P
(∂P/∂T)V = (∂S/∂V)T
(∂V/∂T)P = -(∂S/∂P)T
When dilute aqueous solutions of two salts are mixed, the process is associated with
Decrease in temperature
Increase in temperature
No change in temperature
Change in temperature which is a function of composition
If an ideal solution is formed by mixing two pure liquids in any proportion, then the __________ of mixing is zero
Enthalpy
Volume
Both 'a' & 'b'
Neither 'a' nor 'b'
In an ideal gas mixture, fugacity of a species is equal to its
Vapor pressure
Partial pressure
Chemical potential
None of these
Which of the following equations is obtained on combining 1st and 2nd law of thermodynamics, for a system of constant mass?
dE = Tds - PdV
dQ = CvdT + PdV
dQ = CpdT + Vdp
Tds = dE - PdV
At triple point (for one component system), vapour pressure of solid as compared to that of liquid will be
More
Less
Same
More or less; depending on the system
Molar heat capacity of water in equilibrium with ice at constant pressure is __________ Kcal/kg mole. °K
0
∞
50
100
A refrigeration cycle is the same as a __________ cycle,
Turbine
Heat engine
Reversed heat engine
None of these
Which of the following is not an intensive property?
Chemical potential
Surface tension
Heat capacity
None of these
In an isothermal process on an ideal gas, the pressure increases by 0.5 percent. The volume decreases by about __________ percent.
0.25
0.5
0.75
1
Which of the following is not an intensive property?
Molar heat capacity
Internal energy
Viscosity
None of these
The number of degrees of freedom for an azeotropic mixture in a two component vapour-liquid equilibria is/are
Zero
One
Two
Three
Which of the following is an undesirable characteristic of a refrigerant?
It should be non-explosive
It should have a sub-atmospheric vapor pressure at the temperature in refrigerator coils
Its vapor pressure at the condenser temperature should be very high
None of these
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
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)