In a P-V diagram (for an ideal gas), an isothermal curve will coincide within adiabatic curve (through a point), when
Cp < Cv
Cp = Cv
Cp > Cv
C ≥ Cv
Correct Answer :
B. Cp = Cv
Related Questions
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
If the molar heat capacities (Cp or Cv) of the reactants and products of a chemical reaction are identical, then, with the increase in temperature, the heat of reaction will
Increase
Decrease
Remain unaltered
Increase or decrease; depends on the particular reaction
For an ideal gas, the activity co-efficient is
Directly proportional to pressure
Inversely proportional to pressure
Unity at all pressures
None of these
The variation of heat of reaction with temperature at constant pressure is given by the __________ law.
Kelvin's
Antoines
Kirchoffs
None of these
For an ideal gas, the enthalpy
Increases with rise in pressure
Decreases with rise in pressure
Is independent of pressure
Is a path function
As the time is passing, entropy of the universe
Is increasing
Is decreasing
Remain constant
Data insufficient, can't be predicted
What is the value of ln y (where y = activity co-efficient) for ideal gases?
Zero
Unity
Infinity
Negative
Specific heat of a gas for a reversible adiabatic process is
Negative
Zero
Infinity
None of these
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
Refrigerants commonly used for domestic refrigerators are
Ethyl chloride or methyl chloride
Freon-12
Propane
NH3 or CO2
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
Free energy change of mixing two liquid substances is a function of the
Concentration of the constituents only
Quantities of the constituents only
Temperature only
All (A), (B) and (C)
All gases during throttling process at atmospheric temperature and pressure show a cooling effect except
CO2
H2
O2
N2
What happens in a reversible adiabatic compression?
Heating occurs
Cooling occurs
Pressure is constant
Temperature is constant
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
Which of the following exemplifies an adiabatic process?
Melting of ice
Condensation of alcohol vapor
Sudden bursting of a cycle tube
Evaporation of water
For a multi-component system, the term chemical potential is equivalent to the
Molal concentration difference
Molar free energy
Partial molar free energy
Molar free energy change
Out of the following refrigeration cycles, which one has maximum COP?
Air cycle
Carnot cycle
Ordinary vapor compression cycle
Vapor compression with a reversible expansion engine
(∂E/∂T)V is the mathematical expression for
CV
Enthalpy change
Free energy change
None of these
Free energy changes for two reaction mechanism 'X' and 'Y are respectively - 15 and - 5 units. It implies that X is
Slower than Y
Faster than Y
Three times slower than Y
Three times faster than Y
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
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
Equilibrium constant of a reaction varies with the
Initial concentration of the reactant
Pressure
Temperature
None of these
Co-efficient of Performance (COP) of a refrigerator is the ratio of the
Work required to refrigeration obtained
Refrigeration obtained to the work required
Lower to higher temperature
Higher to lower temperature
Which is an example of closed system?
Air compressor
Liquid cooling system of an automobile
Boiler
None of these
Which of the following is an extensive property of a system?
Heat capacity
Molal heat capacity
Pressure
Concentration
The extensive properties are
Volume, mass and number of moles
Free energy, entropy and enthalpy
Both (A) and (B)
None of these
The unit of fugacity is the same as that of the
Pressure
Temperature
Volume
Molar concentration
An ideal gas is taken around the cycle ABCA as shown in P-V diagram below: The work done by the gas during the cycle is equal to
12 P1V1
6 P1 V1
3 P1V1
P1 V1
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