(∂H/∂T)P is the mathematical expression for
CV
Entropy change
Gibbs free energy
None of these
Correct Answer :
D. None of these
Related Questions
Which of the following is not an equation of state?
Bertholet equation
Clausius-Clapeyron equation
Beattie-Bridgeman equation
None of these
Joule-Thomson co-efficient which is defined as, η = (∂T/∂P)H = 1/Cp (∂H/∂T)P, changes sign at a temperature known as inversion temperature. The value of Joule-Thomson co-efficient at inversion temperature is
0
∞
+ve
-ve
In case of vapour compression refrigeration system, elevating the evaporator temperature (keeping the condenser temperature constant) results in
Enhanced COP
Decreased COP
No change in the value of COP
Increased or decreased COP; depending upon the type of refrigerant
Which of the following is a thermodynamic property of a system?
Concentration
Mass
Temperature
Entropy
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
If two pure liquid constituents are mixed in any proportion to give an ideal solution, there is no change in
Volume
Enthalpy
Both (A) & (B)
Neither (A) nor (B)
As the temperature is lowered towards the absolute zero, the value of ∂(ΔF)/∂T, then approaches
Unity
Zero
That of the heat of reaction
Infinity
A system undergoes a change from a given initial state to a given final state either by an irreversible process or by a reversible process, then (where, Δ S1 and Δ SR are the entropy changes of the system for the irreversible and reversible processes respectively)
Δ S1 is always < Δ SR
Δ S1 is sometimes > Δ SR
Δ S1 is always > Δ SR
Δ S1 is always = Δ SR
For a spontaneous process, free energy
Is zero
Increases
Decreases whereas the entropy increases
And entropy both decrease
One ton of refrigeration is defined as the heat rate corresponding to melting of one ton of ice in one
Hour
Day
Minute
Second
What is the degree of freedom for a system comprising liquid water equilibrium with its vapour?
0
1
2
3
High __________ is an undesirable property for a good refrigerant.
Specific heat
Latent heat of vaporisation
Viscosity
Specific vapor volume
Refrigerants commonly used for domestic refrigerators are
Ethyl chloride or methyl chloride
Freon-12
Propane
NH3 or CO2
Two substances are in equilibrium in a reversible chemical reaction. If the concentration of each substance is doubled, then the value of the equilibrium constant will be
Same
Doubled
Halved
One fourth of its original value
Gibbs-Helmholtz equation is
ΔF = ΔH + T [∂(ΔF)/∂T]P
ΔF = ΔH - TΔT
d(E - TS) T, V < 0
dP/dT = ΔHvap/T.ΔVvap
During adiabatic expansion of gas
Pressure remains constant
Pressure is increased
Temperature remains constant
None of these
Number of components (C), phase (P) and degrees of freedom (F) are related by Gibbs phase rule as
P + F - C = 2
C = P - F + 2
F = C - P - 2
P = F - C - 2
What is the value of ln y (where y = activity co-efficient) for ideal gases?
Zero
Unity
Infinity
Negative
With increase in temperature, the atomic heat capacities of all solid elements
Increases
Decreases
Remains unchanged
Decreases linearly
Pick out the wrong statement.
System (of partially miscible liquid pairs), in which the mutual solubility increases with rise in temperature, are said to possess an upper consolute temperature
Systems, in which the mutual solubility increases with decrease in temperature, are said to possess lower consolute temperature
Nicotine-water system shows both an upper as well as a lower consolute temperature, implying that they are partially miscible between these two limiting temperatures
None of these
Which of the following decreases with increase in pressure?
Melting point of ice
Melting point of wax
Boiling point of liquids
None of these
The necessary and sufficient condition for equilibrium between two phases is
The concentration of each component should be same in the two phases
The temperature of each phase should be same
The pressure should be same in the two phases
The chemical potential of each component should be same in the two phases
The reaction A (l) → R(g) is allowed to reach equilibrium conditions in an autoclave. At equilibrium, there are two phases, one a pure liquid phase of A and the other a vapor phase of A, R and S. Initially A alone is present. The numbers of degrees of freedom are:
1
2
3
0
The number of degrees of freedom for an azeotropic mixture in a two component vapour-liquid equilibria is/are
Zero
One
Two
Three
Which of the following is not a reversible process?
Expansion of an ideal gas against constant pressure
Atmospheric pressure vaporisation of water at 100°C
Solution of NaCl in water at 50°C
None of these
Entropy of a substance remains constant during a/an __________ change.
Reversible isothermal
Irreversible isothermal
Reversible adiabatic
None of these
Maxwell's relation corresponding to the identity, dH = dS = Vdp + Σμi dni is
(∂T/∂V)S, ni = -(∂P/∂S)V, ni
(∂S/∂P)T, ni = (∂V/∂T)P, ni
(∂S/∂V)T, ni = (∂P/∂T)V, ni
(∂T/∂P)S, ni = (∂V/∂S)P, ni
The variation of heat of reaction with temperature at constant pressure is given by the __________ law.
Kelvin's
Antoines
Kirchoffs
None of these
The equation Tds = dE - PdV applies to
Single phase fluid of varying composition
Single phase fluid of constant composition
Open as well as closed systems
Both (B) and (C)
For equilibrium process (i.e. reversible) in an isolated system
ds = 0
ds < 0
ds > 0
ds = Constant