PVγ = Constant (where, γ = Cp/Cv) is valid for a/an __________ process.
Isothermal
Isentropic
Isobaric
Adiabatic
Correct Answer :
D. Adiabatic
Related Questions
Pick out the wrong statement.
Surface tension of a substance vanishes at critical point, as there is no distinction between liquid and vapour phases at its critical point
Entropy of a system decreases with the evolution of heat
Change of internal energy is negative for exothermic reactions
The eccentric factor for all materials is always more than one
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
Gibbs free energy per mole for a pure substance is equal to the
Latent heat of vaporisation
Chemical potential
Molal boiling point
Heat capacity
Free energy
Decreases in all spontaneous (or irreversible) processes
Change during a spontaneous process has a negative value
Remains unchanged in reversible processes carried at constant temperature and pressure
All (A), (B) and (C)
Consider the reaction, C + O2 CO2; ΔH = - 94 kcal. What will be the value of ΔH for the reaction CO2 → C + O2?
-94 kcal
+94 kcal
> 94 kcal
< -94 kcal
A refrigeration cycle is the same as a __________ cycle,
Turbine
Heat engine
Reversed heat engine
None of these
Free energy change at equilibrium is
Zero
Positive
Negative
Indeterminate
Throttling process is a/an __________ process.
Reversible and isothermal
Irreversible and constant enthalpy
Reversible and constant entropy
Reversible and constant enthalpy
Specific __________ does not change during a phase change (e.g. sublimation, melting, vaporisation etc.).
Entropy
Internal energy
Enthalpy
Gibbs free energy
For an ideal gas, the chemical potential is given by
RT d ln P
R d ln P
R d ln f
None of these
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 the equation, PVn = constant, if the value of n = 1, then it represents a reversible __________ process.
Isothermal
Isobaric
Polytropic
Adiabatic
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)
The internal energy of an ideal gas does not change in a reversible __________ process.
Isothermal
Adiabatic
Isobaric
Isometric
The shape of T-S diagram for Carnot Cycle is a
Rectangle
Rhombus
Trapezoid
Circle
The equation, Cp - Cv = R, is true for __________ gas.
No
Any real
Only ideal
Both (B) and (C)
For an exothermic reaction
Only enthalpy change (ΔH) is negative
Only internal energy change (ΔE) is negative
Both ΔH and ΔE are negative
Enthalpy change is zero
The change in Gibbs free energy for vaporisation of a pure substance is
Positive
Negative
Zero
May be positive or negative
Refrigerants commonly used for domestic refrigerators are
Ethyl chloride or methyl chloride
Freon-12
Propane
NH3 or CO2
A two stage compressor is used to compress an ideal gas. The gas is cooled to the initial temperature after each stage. The intermediate pressure for the minimum total work requirement should be equal to the __________ mean of P1 and P2. (where, P1 and P2 are initial and final pressures respectively)
Logarithmic
Arithmetic
Geometric
Harmonic
Which of the following is a thermodynamic property of a system?
Concentration
Mass
Temperature
Entropy
Lenz's law results from the law of conservation of
Mass
Momentum
Energy
None of these
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
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
Joule-Thomson co-efficient for a perfect gas is
Zero
Positive
Negative
None of these
At the critical point of a substance
The surface tension vanishes
Liquid and vapour have the same density
There is no distinction between liquid and vapour phases
All (A), (B) and (C)
Cv is given by
(∂E/∂T)V
(∂E/∂V)T
(∂E/∂P)V
(∂V/∂T)P
Pick out the wrong statement.
Enthalpies of all elements in their standard states are assumed to be zero
Combustion reactions are never endothermic in nature
Heat of reaction at constant volume is equal to the change in internal energy
Clausius-Clapeyron equation is not applicable to melting process
Maximum work that could be secured by expanding the gas over a given pressure range is the __________ work.
Isothermal
Adiabatic
Isentropic
None of these
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