Third law of thermodynamics is helpful in
Prediction of the extent of a chemical reaction
Calculating absolute entropies of substances at different temperature
Evaluating entropy changes of chemical reaction
Both (B) and (C)
Correct Answer :
D. Both (B) and (C)
Related Questions
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
Pick out the wrong statement.
A refrigeration cycle violates the second law of thermodynamics
Refrigeration cycle is normally represented by a temperature vs. entropy plot
In a refrigerator, work required decreases as the temperature of the refrigerator and the temperature at which heat is rejected increases
One ton of refrigeration is equivalent to the rate of heat absorption equal to 3.53 kW
Entropy change for an irreversible isolated system is
∞
0
< 0
> 0
The temperature at which both liquid and gas phases are identical, is called the __________ point.
Critical
Triple
Freezing
Boiling
PVy = constant, holds good for an isentropic process, which is
Reversible and isothermal
Isothermal and irreversible
Reversible and adiabatic
Adiabatic and irreversible
Water on heating from 1 to 4°C
Contracts
Expands
Has same volume
May contract or expand
Fugacity of a component in an ideal gas mixture is equal to the partial pressure of that component in the mixture. The fugacity of each component in a stable homogeneous solution at constant pressure and temperature __________ as its mole fraction increases.
Decreases
Decreases exponentially
Increases
Remain constant
In an ideal refrigeration cycle, the change in internal energy of the fluid is
+ve
-ve
0
Either of the above three; depends on the nature of refrigerant
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
Which of the following behaves most closely like an ideal gas?
He
N2
O2
H2
The expression for entropy change, ΔS = n Cp . ln (T2/T1), is valid for the __________ of a substance.
Simultaneous pressure & temperature change
Heating
Cooling
Both (B) and (C)
Fundamental principle of refrigeration is based on the __________ law of thermodynamics.
Zeroth
First
Second
Third
Keeping the pressure constant, to double the volume of a given mass of an ideal gas at 27°C, the temperature should be raised to __________ °C.
270
327
300
540
When a system in equilibrium is subjected to a change in temperature, pressure or concentration, the equilibrium is displaced in a direction which tends to undo the effect of the change. This is called the
Le-Chatelier principle
Kopp's rule
Law of corresponding state
Arrhenius hypothesis
Specific volume of an ideal gas is
Equal to its density
The reciprocal of its density
Proportional to pressure
None of these
The standard state of a gas (at a given temperature) is the state in which fugacity is equal to
Unity
Activity
Both (A) & (B)
Neither (A) nor (B)
Pick out the extensive property out of the following.
Surface tension
Free energy
Specific heat
Refractive index
While dissolving a gas into a liquid at a constant temperature, the ratio of the concentration of the gas in the solution phase and in the gaseous phase is
Infinity
Unity
Constant
Negative
Gibbs-Helmholtz equation is
ΔF = ΔH + T [∂(ΔF)/∂T]P
ΔF = ΔH - TΔT
d(E - TS) T, V < 0
dP/dT = ΔHvap/T.ΔVvap
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
Internal energy change of a system over one complete cycle in a cyclic process is
Zero
+ve
-ve
Dependent on the path
When liquid and vapour phase of multi-component system are in equilibrium (at a given temperature and pressure), then chemical potential of each component is
Same in both the phases
Zero in both the phases
More in vapour phase
More in liquid phase
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
At normal boiling point, molar entropy of vaporisation is __________ Joule/K°.mole.
72
92
142
192
Heating of water under atmospheric pressure is an __________ process.
Isochoric
Isobaric
Adiabatic
Isothermal
When dilute aqueous solutions of two salts are mixed, the process is associated with
Decrease in temperature
Increase in temperature
No change in temperature
Change in temperature which is a function of composition
Any substance above its critical temperature exists as
Saturated vapour
Solid
Gas
Liquid
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
The kinetic energy of gas molecule is zero at
0°C
273°C
100°C
-273°C
Gibbs-Duhem equation
States that n1dμ1 + n2dμ2 + ....njdμj = 0, for a system of definite composition at constant temperature and pressure
Applies only to binary systems
Finds no application in gas-liquid equilibria involved in distillation
None of these