The entropy change in a reversible isothermal process, when an ideal gas expands to four times its initial volume is
R loge 4
R log10 4
Cv log10 4
Cv loge 4
Correct Answer :
A. R loge 4
Related Questions
Third law of thermodynamics is concerned with the
Value of absolute entropy
Energy transfer
Direction of energy transfer
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
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
Entropy change in case of reversible adiabatic process is
Minimum
Zero
Maximum
Indeterminate
Measurement of thermodynamic property of temperature is facilitated by __________ law of thermodynamics.
1st
Zeroth
3rd
None of these
Melting of ice is an example of an __________ process.
Adiabatic
Isothermal
Isometric
None of these
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
A change in state involving a decrease in entropy can be spontaneous, only if
It is exothermic
It is isenthalpic
It takes place isothermally
It takes place at constant volume
Pick out the wrong statement.
A closed system does not permit exchange of mass with its surroundings but may permit exchange of energy.
An open system permits exchange of both mass and energy with its surroundings
The term microstate is used to characterise an individual, whereas macro-state is used to designate a group of micro-states with common characteristics
None of the above
Partial molar free energy of an element A in solution is same as its
Chemical potential
Activity
Fugacity
Activity co-efficient
An irreversible process
Is the analog of linear frictionless motion in machines
Is an idealised visualisation of behaviour of a system
Yields the maximum amount of work
Yields an amount of work less than that of a reversible process
The number of degrees of freedom at the triple point of water is
0
1
2
3
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 variation of heat of reaction with temperature at constant pressure is given by the __________ law.
Kelvin's
Antoines
Kirchoffs
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
Lenz's law results from the law of conservation of
Mass
Momentum
Energy
None of these
The equation, (d loge PA/d loge xA) = (d loge PA/d loge xB) 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
During the phase transition, __________ changes.
Pressure
Volume
Temperature
All (A), (B) and (C)
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
Requisites of a reversible process is that the
System and surroundings pressure be equal
Friction in the system should be absent
System and surroundings temperature be equal
None of these
dW and dq are not the exact differential, because q and W are
State functions
Path functions
Intensive properties
Extensive properties
Compressibility factor of a gas is
Not a function of its pressure
Not a function of its nature
Not a function of its temperature
Unity, if it follows PV = nRT
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
Activity co-efficient is a measure of the
Departure from ideal solution behaviour
Departure of gas phase from ideal gas law
Vapour pressure of liquid
None of these
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
Specific/molar Gibbs free energy for a pure substance does not change during
Sublimation
Vaporisation
Melting
Either (A), (B) or (C)
In polytropic process (PVn = constant), if n = 1; it means a/an __________ process.
Adiabatic
Reversible
Isothermal
None of these
When pressure is applied on the system, ice ↔ water, then
Equilibrium cannot be established
More ice will be formed
More water will be formed
Evaporation of water will take place
Pick out the wrong statement.
An ideal liquid or solid solution is defined as one in which each component obeys Raoult's law
If Raoult's law is applied to one component of a binary mixture; Henry's law or Raoult's law is applied to the other component also
Henry's law is rigorously correct in the limit of infinite dilution
None of these
Joule-Thomson experiment is
Isobaric
Adiabatic
Isenthalpic
Both (B) & (C)