Thermodynamics Part 3 Flashcards
Entropy is a/an
state function
macroscopic property
extensive property
none of these
none of these
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.
same
4 kg moles of an ideal gas expands in vacuum spontaneously. The work done is
4 J
infinity
0
8 J
0
Which of the following is not correct for a reversible adiabatic process ?
TVγ-1 = constant
p1-γ.TY = constant
PVγ = constant
none of these
none of these
The efficiency of a Carnot heat engine operating between absolute temperatures T1 and T2 (when, T1 > T2) is given by (T1 - T2)/T1. The co-efficient of performance (C.O.P.) of a Carnot heat pump operating between T1 and T2 is given by
T1/(T1-T2)
T2/(T1-T2)
T1/T2
T2/R1
T1/(T1-T2)
Throttling (Joule-Thomson effect) process is a constant __________ process.
enthalpy
entropy
pressure
none of these
enthalpy
Boiling of liquid is accompanied with increase in the
vapor pressure.
specific Gibbs free energy.
specific entropy.
all of these
vapor pressure.
Change of state namely evaportation condensation, freezing and melting is an __________ process.
isothermal
adiabatic
isobaric
isochoric
isothermal
Which of the following is not an equation of state?
Bertholet equation
Clausius Clayperon equation
Beattie-Bridgeman equation
None of these
Clausius Clayperon equation
A gas shows deviation from ideal behaviour at
low pressure and high temperature.
low pressure and low temperature.
low temperature and high pressure.
high temperature and high pressure.
low temperature and high pressure.
The difference between isothermal compressibility and adiabatic compressibility for an ideal gas is
0
+ve
-ve
infinity
+ve
The expression for entropy change given by, delta-S = - nR ln (P2/P1), holds good for
expansion of a real gas.
reversible isothermal volume change.
heating of an ideal gas.
cooling of a real gas.
reversible isothermal volume change.
With increase in temperature, the internal energy of a substance
increases
decreases
remains unchanged
may increase or decrease; depends on the substance
increases
It is desired to bring about a certain change in the state of a system by performing work on the system under adiabatic conditions.
The amount of work needed is path dependent.
Work alone can not bring out such a change of state.
The amount of work needed is independent of path.
More information is needed to conclude anything about the path dependence or otherwise of the work needed.
The amount of work needed is path dependent.
For a constant pressure reversible process, the enthalpy change (delta-H) of the system is
Cv.dT
Cp.dT
integ Cv.dT
integ Cp.dT
integ Cv.dT
The work done in isothermal compression compared to that in adiabatic compression will be
less
more
same
more or less depending upon the extent of work done
more
For organic compounds, group contribution method can be used for the estimation of
critical properties.
specific gravity.
specific volume.
thermal conductivity.
critical properties.
group contributin critical properties
Specific __________ does not change during phase change at constant temperature and pressure.
entropy
Gibbs energy
internal energy
enthalpy
Gibbs energy
When liquid and vapour phases of one component system are in equilibrium (at a given temperature and pressure), the molar free energy is
more in vapour phase.
more in liquid phase.
same in both the phases.
replaced by chemical potential which is more in vapour phase.
same in both the phases.
Heat evolved/absorbed during conversion of a substance from one allotropic form to another is termed as the heat of
fusion
vaporisation
transition
none of these
transition
What happens in a reversible adiabatic compression ?
Heating occurs
Cooling occurs
Pressure is constant
Temperature is constant
Heating occurs
Sublimation temperature of dry ice (solid CO2) is __________ C.
-273
0
-78
5
-78
If atmospheric temperature and dew point are nearly equal, then the relative humidity is
zero
0.5
almost 100%
unpredictable
almost 100%
Entropy change in case of reversible adiabatic process is
minimum
zero
maximum
indeterminate
zero
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
same
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
more
Mollier chart is a __________ plot.
pressure vs enthalpy
pressure vs volume
enthalpy vs entropy
temperature vs entropy
enthalpy vs entropy
Variation of equilibrium pressure with temperature for any two phases of a given substances is given by the __________ equation.
Gibbs-Duhem
Maxwell’s
Clayperon
none of these
Clayperon
Pick out the undesirable property for a good refrigerant.
high thermal conductivity
low freezing point
large latent heat of vaporisation
high viscosity
high viscosity
Isotherm on an enthalpy-concentration diagram, for an ideal solution will be a
straight line
sine curve
parabola
hyperbola
straight line
The fusion of a crystalline solid at its melting point to form a liquid at the same temperature is accompanied by
decrease in enthalpy corresponding to evolution of heat.
decrease of entropy.
increase in enthalpy corresponding to absorption of heat.
no change in enthalpy.
increase in enthalpy corresponding to absorption of heat.
fusion o crystalline - enthalpy increase
Melting of ice is an example of an __________ process.
adiabatic
isothermal
isometric
none of these
isothermal
A cylinder contains 640 gm of liquid oxygen. The volume occupied (in litres) by the oxygen, when it is released and brought to standard conditions (0 C, 760 mm Hg) will be __________ litres.
448
224
22.4
data insufficient; can’t be computed
448
Rotary lime kiln is an example of a/an __________ system.
closed
open
isolated
non-thermodynamic
open
Heat of reaction is
dependent on pressure only.
dependent on temperature only.
dependent on both pressure and temperature.
independent of temperature changes.
dependent on both pressure and temperature.
The expression, , is for the____of an ideal gas.
compressibility
work done under adiabatic contition
work done under isothermal condition
co-efficient of thermal expansion
work done under isothermal condition
What happens in a reversible adiabatic expansion process ?
Heating takes place.
Cooling takes place.
Pressure is constant.
Temperature is constant.
Cooling takes place.
Degree of freedom of a system consisting of a gaseous mixture of H2 and NH3 will be
0
1
2
3
3
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 (aP/aV)s and the slope of the reversible isothermal line (aP/aV)T are related as (where, y = Cp/Cv)
(aP/aV)S = (aP/aV)T
(aP/aV)S = [(aP/aV)T]^Y
(aP/aV)S = y(aP/aV)T
(aP/aV)S = 1/y(aP/aV)T
(aP/aV)S = y(aP/aV)T
Pick out the wrong statement.
The net change in entropy in any reversible cycle is always zero.
The entropy of the system as a whole in an irreversible process increases.
The entropy of the universe tends to a maximum.
The entropy of a substance does not remain constant during a reversible adiabatie change.
The entropy of the universe tends to a maximum.
wrong maximum entropy universe
Fugacity co-efficient of a substance is the ratio of its fugacity to
mole fraction
activity
pressure
activity co-efficient
activity co-efficient
Dryness fraction of wet steam is defined as the ratio of mass of vapour in the mixture to the mass of mixture __________ calorimeter is not used for measuring the dryness fraction of steam.
Bomb
Separating
Bucket
Throttling
Bomb
As the time is passing, entropy of the universe
is increasing
is decreasing
remains constant
data insufficient, can’t be predicted
is increasing
Which of the following processes can not be made reversible even under ideal condition of operation?
Free expansion of a gas.
Compression of air in a compressor.
Expansion of steam in a turbine.
all of these.
Free expansion of a gas.
The relation connecting the fugacities of various components in a solution with one another and to composition at constant temperature and pressure is called the __________ equation.
Gibbs-Duhem
Van Laar
Gibbs-Helmholtz
Margules
Gibbs-Duhem
Which of the following identities can be most easily used to verify steam table data for superheated steam.
(aT/aV)S = (ap/aS)V
(aT/aP)S = (aV/aS)P
(aP/aT)V = (aS/aV)T
(aV/aT)P = -(aS/aP)T
(aV/aT)P = -(aS/aP)T
In the equation PVn = constant, if the value of n = y = Cp/Cv, then it represents a reversible __________ process.
isothermal
adiabatic
isentropic
polytropic
isentropic
The ammonia synthesis reaction represented by N2 + 3H2 <~> 2NH3 ; delta-H = - 22.4 kcal, is
endothermic
exothermic
isothermal
adiabatic
exothermic
With increase in temperature, the atomic heat capacities of all solid elements
increases
decreases
remains unchanged
decreases linearly
increases
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
lowest
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.
more pronounced
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.
superheated vapour.
An isentropic process is carried out at constant
volume
pressure
temperature
all of these
volume
All gases except __________ shows a cooling effect during throttling process at atmospheric temperature and pressure.
oxygen
nitrogen
air
hydrogen
hydrogen
High pressure steam is expanded adiabati-cally and reversibly through a well insulated turbine, which produces some shaft work. If the enthalpy change and entropy change across the turbine are represented by delta-H and delta-S respectively for this process:
delta- H = 0 and delta-S = 0.
delta- H is not equal to 0 and delta-S = 0.
delta- H is not equal to 0 and delta-S is not equal to 0.
delta- H = 0 and delta-S is not equal to 0.
delta- H is not equal to 0 and delta-S = 0.
The necessary condition for phase equilibrium in a multiphase system of N components is that the
chemical potentials of a given component should be equal in all phases.
chemical potentials of all components should be same in a particular phase.
sum of the chemical potentials of any given component in all the phases should be the same.
none of these.
chemical potentials of a given component should be equal in all phases.
Compressibility factor-reduced pressure plot on reduced co-ordinates facilitates
use of only one graph for all gases.
covering of wide range.
easier plotting.
more accurate plotting.
use of only one graph for all gases.
Which of the following is not an intensive property ?
Molar heat capacity
Internal energy
Viscosity
None of these
Internal energy
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 liquified, 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.
At constant pressure, solubility of a gas in a liquid diminishes with rise in temperature.
Gibbs phase rule finds application, when heat transfer occurs by
conduction
convection
radiation
condensation
condensation
condensation - gibbs phare rule
Absorption/evolution of heat during conversion of a substance from one allotropic form to another is termed as the heat of
sublimation
fusion
transition
vaporisation
transition
Ideal gas law is applicable at
low T, low P
high T, high P
low T, high P
high T, low P
high T, low P
Reduced pressure of a gas is the ratio of its
pressure to critical pressure.
critical pressure to pressure.
pressure to pseudocritical pressure.
pseudocritical pressure to pressure.
pressure to critical pressure.
For a reversible process involving only pressure-volume work
(dF)T, p < 0
(dF)T, p > 0
(dF)T, p = 0
(dA)T, v < 0
(dF)T, p = 0
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)
300(32/7)
Entropy change for an irreversible process taking system and surrounding together is
0
> 0
< 0
none of these
> 0
In a homogeneous solution, the fugacity of a component depends upon the
pressure
composition
temperature
all of these
all of these
For an incompressible fluid, the __________ is a function of both pressure as well as temperature.
internal energy
enthalpy
entropy
all of these
enthalpy
An ideal monoatomic gas is taken round the cycle ABCDA as shown below in the P-V diagram (1) The work done during the cycle is
PV
2PV
PV/2
0
PV
One ton of refrigeration capacity is equivalent to the heat removal rate of
50 k cal/hr
200 BTU/hr
200 BTU/minute
200 BTU/day
200 BTU/minute
What is the degree of freedom for a system comprising liquid water equilibrium with its vapour ?
0
1
2
3
1
Equilibrium constant of a reaction varies with the
initial concentration of the reactant.
pressure.
temperature.
none of these.
temperature.
Third law of thermodynamics is concerned with the
value of absolute entropy.
energy transfer.
direction of energy transfer.
none of these.
value of absolute entropy.
Claude’s liquefaction process employs the cooling of gases by
expansion in an engine
following a constant pressure cycle
throttling
none of these
expansion in an engine
Gibbs free energy (F) is defined as
F = E - TS
F = H - TS
F = H + TS
F = E + TS
F = H - TS
The expression for entropy change given by, delta-S = nR ln (V2/V1) + nCv ln (T2/T1) is valid for
reversible isothermal volume change.
heating of a substance.
cooling of a substance.
simultaneous heating and expansion of an ideal gas.
simultaneous heating and expansion of an ideal gas.
The second law of thermodynamics states that
the energy change of a system undergoing any reversible process is zero.
it is not possible to transfer heat from a lower temperature to a higher temperature.
the total energy of system and surrounding remains the same.
none of the above.
none of the above.
Internal energy of an ideal gas
increases with increase in pressure.
decreases with increase in temperature.
is independent of temperature.
none of these.
none of these.
A refrigerator works on the principle of __________ law of thermodynamics.
zeroth
first
second
third
second
Pick out the wrong statement.
The conversion for a gas phase reaction increases with decrease in pressure, if there is an increase in volume accompanying the reaction.
With increase in temperature, the equilibrium constant increases for an exothermic reaction.
The equilibrium constant of a reaction depends upon temperature only.
The conversion for a gas phase reaction increases with increase in pressure, if there is a decrease in volume accompanying the reaction.
With increase in temperature, the equilibrium constant increases for an exothermic reaction.
Pick out the wrong statement.
Enthalpies of all elements in their standard states are assumed to be zero.
Combustion reactions are never en-dothermic in nature.
Heat of reaction at constant volume is equal to the change in internal energy.
Claussius-clayperon equation is not applicable to melting process.
Claussius-clayperon equation is not applicable to melting process.
Which of the following is affected by the temperature ?
Fugacity
Activity co-efficient
Free energy
all of these
all of these
The molar excess Gibbs free energy, g^E, for a binary liquid mixture at T and P is given by, (g^E/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 . X2^2
Ax1
Ax2
Ax1^2
A . X2^2
The adiabatic throttling process of a perfect gas is one of constant enthalpy
in which there is a temperature drop.
which is exemplified by a non-steady flow expansion.
which can be performed in a pipe with a constriction.
in which there is an increase in temperature.
which can be performed in a pipe with a constriction.
For spontaneous changes in an isolated system (S = entropy)
ds = 0
ds <0
ds > 0
ds = Constant
ds > 0
A gas performs the maximum work, when it expands
non-uniformly
adiabatically
isobarically
isothermally
isobarically
There is a change in __________ during the phase transition.
volume
pressure
temperature
all a, b & c
volume
Which of the following is Virial equation of state?
(p + a/V^2)(V - b) = nRT
PV = nRT
PV = A + B/V + C/V^2 + D/V^3 + …
PV = A + B/V + C/V^2 + D/V^3 + …
Pressure-enthalpy chart is useful in refrigeration. The change in internal energy of an ideal fluid used in ideal refrigeration cycle is
positive
negative
zero
infinity
zero
First law of thermodynamics deals with the
direction of energy transfer.
reversible processes only.
irreversible processes only.
none of these.
direction of energy transfer.
Henry’s law is closely obeyed by a gas, when its __________ is extremely high.
pressure
solubility
temperature
none of these
none of these
A solute distributes itself between two non-miscible solvents in contact with each other in such a way that, at a constant temperature, the ratio of its concentrations in two layers is constant, irrespective of its total amount”. This is
the distribution law.
followed from Margule’s equation.
a corollary of Henry’s law.
none of these.
the distribution law.
A solid is transformed into vapour without going to the liquid phase at
triple point
boiling point
below triple point
always
triple point
A gas mixture of three components is brought in contact with a dispersion of an organic phase in water. The degree of freedom of the system are
4
3
5
6
3
1m^3 of an ideal gas at 500 K and 1000 kPa expands reversibly to 5 times its initial volume in an insulated container. If the specific heat capacity (at constant pressure) of the gas is 21 J/mole . K, the final temperature will be
35 K
174 K
274 K
154 K
274 K
For a thermodynamic system containing ‘x’ chemical species, the maximum number of phases that can co-exist at equilibrium is
x
x + 1
x + 2
x + 3
x + 2
A reasonably general expression for vapour-liquid phase equilibrium at low to moderate pressure is phi-i yi P = Yi xi fi where, phi is a vapor fugacity component, Yi is the liquid activity co-efficient and fi is the fugacity of the pure component i. the Ki value (Yi = Ki xi) is therefore, in general a function of
temperature only.
temperature and pressure only.
temperature, pressure and liquid composition xi only.
temperature, pressure, liquid composition xi and vapour composition yi.
temperature, pressure and liquid composition xi only.
Standard temperature and pressure (S.T.P.) is
0 C and 750 mm Hg
15 C and 750 mm Hg
0 C and 1 kgf/cm^2
15 C and 1 kgf/cm^2
0 C and 750 mm Hg
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/cm^2.
20 C and 760 mm Hg.
The minimum number of phases that can exist in a system is
0
1
2
3
1
Enthalpy changes over a constant pressure path are always zero for __________ gas.
any
a perfect
an easily liquefiable
a real
a perfect
The fugacity of a gas in a mixture is equal to the product of its mole fraction and its fugacity in the pure state at the total pressure of the mixture”. This is
the statement as per Gibbs-Helmholtz
called Lewis-Randall rule
Henry’s law
none of these
called Lewis-Randall rule
__________ does not change during phase transformation processes like sublimation, melting & vaporisation.
Entropy
Gibbs free energy
Internal energy
all of these
Gibbs free energy
Which one is true for a throttling process ?
A gas may have more than one inversion temperatures.
The inversion temperature is different for different gases.
The inversion temperature is same for all gases.
The inversion temperature is the temperature at which Joule-Thomson co-efficient is infinity.
The inversion temperature is different for different gases.
Choose the condition that must be specified in order to liquify CO2 (triple point for CO2 is - 57 C and 5.2 atm).
Pressure must be kept below 5.2 atm.
Temperature must be kept above - 57 C.
Pressure must be kept below 5.2 atm. and temperature must be kept above 57 C.
Pressure and temperature must be kept below 5.2 atm. and - 57 C respectively.
Pressure and temperature must be kept below 5.2 atm. and - 57 C respectively.
One mole of nitrogen at 8 bar and 600 K is contained in a piston-cylinder arrangement. It is brought to 1 bar isothermally against a resisting pressure of 1 bar. The work done (in Joules) by the gas is
30554
10373
4988.4
4364.9
10373
Lenz’s law results from the law of conservation of
mass
momentum
energy
none of these
energy
LLE Lenz’s law enegy
In the equation, PVn = constant, if the value of n is in between 1 and y (i.e. Cp/Cv), then it represents a reversible __________ process.
isometric
polytropic
isentropic
isobaric
polytropic
Throttling process is a/an __________ process.
reversible and isothermal
irreversible and constant enthalpy
reversible and constant entropy
reversible and constant enthalpy
irreversible and constant enthalpy
throttling - irrev.const.ent.
The main feature of Carnot refrigeration cycle is that, it
does not need the addition of external work for its functioning.
transfers heat from high temperature to low temperature.
accomplishes the reverse effect of the heat engine.
none of these.
accomplishes the reverse effect of the heat engine.
Charles’ law for gases states that
V/2 = Constant
V infinity 1/T
V infinity 1/p
PV/T = Constant
V/2 = Constant
If heat contents of CH4, C2H4 and C3H8 are -17.9, 12.5 and -24.8 kcal/mole respectively, than delta-H for the reaction CH4(g) + C2H4(g) C3H8(g) will be __________ Kcal.
-19.4
-30.2
55.2
-55.2
-19.4
Helmholtz free energy (A) is defined as
A = H - TS
A = E - TS
A = H + TS
none of these
A = E - TS
As pressure approaches zero, the ratio of fugacity to pressure (f/P) for a gas approaches
zero
unity
infinity
an indeterminate value
unity
For any system, what is the minimum number of degrees of freedom?
1
0
2
3
0
At 60 C, vapour pressure of methanol and water are 84.562 kPa and 19.953 kPa respectively. An aqueous solution of methanol at 60 C exerts a pressure of 39.223 kPa; the liquid phase and vapour phase mole fractions of methanol are 0.1686 and 0.5714 respectively. Activity co-efficient of methanol is
1.572
1.9398
3.389
4.238
1.572
The variation of heat of reaction with temperature at constant pressure is given by the __________ law.
Kelvin’s
Antonie’s
Kirchoffs
none of these
Kirchoffs
At absolute zero temperature, the __________ of the gas is zero.
pressure
volume
mass
none of these
volume
Which of the following equations is used for the prediction of activity co-efficient from experiments ?
Van Laar equation
Margules equation
Wilson’s equation
all of these
all of these
The equation, , applicable to a binary solution of components. A and B in equilibrium with their vapors at constant temperature and pressure is called the __________ equation.
Van Laar
Margules
Gibbs-Duhem
Gibbs-Duhem-Margules
Gibbs-Duhem-Margules
Entropy of a substance remains constant during a/an __________ change.
reversible isothermal
irreversible isothermal
reversible adiabatic
none of these
reversible adiabatic
Gases are cooled in Joule-Thomson expansion, when it is __________ inversion temperature.
below
at
above
either ‘b’ or ‘c’
below
PVy = constant, holds good for an isentropic process, which is
reversible and isothermal.
isothermal and irreversible.
reversible and adiabatic.
adiabatic and irreversible.
reversible and adiabatic.
Which of the following behaves most closely like an ideal gas ?
He
N2
O2
H2
He
In the reaction, C + O2 -> CO2 ; delta-H = - 94 kcal. What is the heat content (enthalpy)of O2?
-94 kcal
> -94 kcal
< - 94 kcal
zero
zero
When a system is in equilibrium for all possible processes, the differential or finite change of entropy is
< 0
> 0
0
none of these
< 0
A system is said to be at equilibrium, if the entropy of the system has reached __________ value.
minimum
zero
maximum
none of these
maximum
In the equation, PV^n = constant, if the value of n = +- infinity, then it represents a reversible __________ process.
adiabatic
isometric
isentropic
isothermal
isometric
Degree of freedom of the system ice-water-vapour will be
0
1
2
3
0
A system in which there is exchange of energy but not of mass, is called a/an __________ system.
isolated
open
insulated
closed
closed
The point at which all the three (solid, liquid and gas) phases co-exist, is known as the __________ point.
freezing
triple
boiling
Boyle
triple
In an ideal gas mixture, fugacity of a species is equal to its
vapor pressure
partial pressure
chemical potential
none of these
partial pressure
The third law of thermodynamics states that the
heat capacity of a crystalline solid is zero at absolute zero temperature.
heat transfer from low temperature to high temperature source is not possible without external work.
gases having same reduced properties behave similarly.
none of these.
heat capacity of a crystalline solid is zero at absolute zero temperature.
Consider the reaction, C + O2 <~> CO2 ;delta-H = - 94 kcal. What will be the value of delta-H for the reaction CO2 C + O2 ?
-94 kcal
+ 94 kcal
> 94 kcal
< -94 kcal
+ 94 kcal
Which is not a state function ?
Specific volume
Work
Pressure
Temperature
Work
For an ideal liquid solution, which of the following is unity ?
Activity
Fugacity
Activity co-efficient
Fugacity co-efficient
Activity co-efficient
In the decomposition of PCl5 represented by, PCl5 <~> PCl3 + Cl2, decrease in the pressure of the system will __________ the degree of dissociation of PCl5.
increase
decrease
not alter
none of these
increase
To obtain integrated form of Clausius-Clayperon equation,(1), from the exact Clayperon equafion, it is assumed that the
volume of the liquid phase is negligible compared to that of vapour phase.
vapour phase behaves as an ideal gas.
heat of vaporisation is independent of temperature.
all of these.
all of these.
In case of an __________ process, the temperature of the system increases.
isothermal compression
isothermal expansion
adiabatic expansion
adiabatic compression
adiabatic compression
Cp of a gas at its critical temperature and pressure
becomes zero.
becomes infinity.
equals 1 kcal/kmol K.
equals 0.24 kcal/kmol K.
equals 1 kcal/kmol K.
Trouton’s ratio is given by (where lambda-b, = molal heat of vaporisation of a substance at its normal boiling point, kcal/kmol Tb = normal boiling point, K )
lambda-b/Tb
Tb/lambda-b
sqrt(lambda-b/Tb)
sqrt(Tb/lambda-b)
lambda-b/Tb
Which of the following is true for Virial equation of state ?
Virial co-efficients are universal constants.
Virial co-efficients ‘B’ represents three body interactions.
Virial co-efficients are function of temperature only.
For some gases, Virial equations and ideal gas equations are the same.
Virial co-efficients are function of temperature only.
Molar heat capacity of water in equilibrium with ice at constant pressure is __________ Kcal/kg mole . K
0
∞
50
100
∞
A gas can be liquified 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
less than or equal to
For an ideal gas, the internal energy depends upon its __________ only.
molecular size
temperature
volume
pressure
temperature
Compound having large heat of formation is
more stable.
less stable.
not at all stable (like nascent O2).
either more or less stable ; depends on the compound.
more stable.
Second law of thermodynamics is concerned with the
amount of energy transferred.
direction of energy transfer.
irreversible processes only.
non-cyclic processes only.
direction of energy transfer.
