The difference between isothermal compressibility and adiabatic compressibility for an ideal gas is
0
+ve
-ve
∞
Correct Answer :
B. +ve
Related Questions
Lowering of condenser temperature (keeping the evaporator temperature constant) in case of vapour compression refrigeration system results in
Increased COP
Same COP
Decreased COP
Increased or decreased COP; depending upon the type of refrigerant
Pick out the correct statement.
The available energy in an isolated system for all irreversible (real) processes decreases
The efficiency of a Carnot engine increases, if the sink temperature is decreased
The reversible work for compression in non-flow process under isothermal condition is the change in Helmholtz free energy
All (A), (B) and (C)
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
Chemical potential of ith component of a system is given by
μi = (∂F/∂ni)T, P, ni
μi = (∂A/∂ni)T, P, ni
μi = (∂F/∂ni)T, P
μi = (∂A/∂ni)T, P
At a given temperature, the volume of a gas dissolved in a solvent __________ with increase in pressure.
Increases
Decreases
Remains unchanged
May increase or decrease; depends on the gas
Minimum number of phases that exists in a system is 1. Number of chemical species in a colloidal system is
1
2
3
4
Translational kinetic energy of molecules of an ideal gas is proportional to (where, T = absolute temperature of the gas)
T
√T
T2
1/√T
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
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
Specific/molar Gibbs free energy for a pure substance does not change during
Sublimation
Vaporisation
Melting
Either (A), (B) or (C)
4 kg moles of an ideal gas expands in vacuum spontaneously. The work done is
4 J
∞
0
8 J
Pick out the Clausius-Clapeyron equation from the following:
dP/dT = ΔH/TΔV
ln P = - (ΔH/RT) + constant
ΔF = ΔH + T [∂(ΔF)/∂T]P
None of these
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
Pick out the wrong statement.
Trouton's ratio of non-polar liquids is calculated using Kistyakowsky equation
Thermal efficiency of a Carnot engine is always less than 1
An equation relating pressure, volume and temperature of a gas is called ideal gas equation
None of these
Refrigeration capacity of a household refrigerator may be round about __________ tons.
0.15
1.5
4.5
6.5
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
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
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 gas law (PV = RT) is true for an __________ change.
Isothermal
Adiabatic
Both (A) & (B)
Neither (A) nor (B)
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
Which of the following will increase the volume of a real gas by four times?
Doubling the absolute temperature as well as pressure of the gas
Reducing pressure to one fourth at constant temperature
Reducing temperature to one fourth at constant pressure
Reducing the temperature to half and doubling the pressure
A liquid under pressure greater than its vapour pressure for the temperature involved is called a __________ liquid.
Sub-cooled
Saturated
Non-solidifiable
None of these
The change in Gibbs free energy for vaporisation of a pure substance is
Positive
Negative
Zero
May be positive or negative
In the reaction; N2 + O2 2NO, increasing the pressure will result in
Shifting the equilibrium towards right
Shifting the equilibrium towards left
No change in equilibrium condition
None of these
Sublimation temperature of dry ice (solid CO2) is __________ °C.
-273
0
-78
5
During the phase transition, __________ changes.
Pressure
Volume
Temperature
All (A), (B) and (C)
When a gas is expanded from high pressure region to low pressure region; temperature change occurs. This phenomenon is related to the
Gibbs-Duhem equation
Gibbs-Helmholtz equation
Third law of thermodynamics
Joule-Thomson effect
If the vapour pressure at two temperatures of a solid phase in equilibrium with its liquid phase are known, then the latent heat of fusion can be calculated by the
Maxwell's equation
Clausius-Clapeyron Equation
Van Laar equation
Nernst Heat Theorem
The number of degrees of freedom at the triple point of water is
0
1
2
3
At equilibrium condition, the chemical potential of a material in different phases in contact with each other is equal. The chemical potential for a real gas (μ) is given by (where, μ = standard chemical potential at unit fugacity (f° = 1 atm.) and the gas behaves ideally.)
μ° + RT ln f
μ°+ R ln f
μ° + T ln f
μ° + R/T ln f