Melting of wax is accompanied with __________ in entropy.
Increase
Decrease
No change
None of these
Correct Answer :
A. Increase
Related Questions
For an ideal solution, the value of activity co-efficient is
0
1
< 1
> 1
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
In a working refrigerator, the value of COP is always
0
< 0
< 1
> 1
Which of the following is a thermodynamic property of a system?
Concentration
Mass
Temperature
Entropy
A gas performs the maximum work, when it expands
Non-uniformly
Adiabatically
Isobarically
Isothermally
For an ideal gas, the activity co-efficient is
Directly proportional to pressure
Inversely proportional to pressure
Unity at all pressures
None of these
__________ decreases during adiabatic throttling of a perfect gas.
Entropy
Temperature
Enthalpy
Pressure
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
The freezing point of a liquid decreases when the pressure is increased, if the liquid __________ while freezing.
Contracts
Expands
Does not change in volume
Either (A), (B) or (C)
Boiling of liquid is accompanied with increase in the
Vapor pressure
Specific Gibbs free energy
Specific entropy
All (A), (B) and (C)
Molar heat capacity of water in equilibrium with ice at constant pressure is __________ Kcal/kg mole. °K
0
∞
50
100
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)
Cv for an ideal gas
Does not depend upon temperature
Is independent of pressure only
Is independent of volume only
Is independent of both pressure and volume
The rate at which a substance reacts is proportional to its active mass and the rate of a chemical reaction is proportional to the product of active masses of the reacting substances. This is the
Lewis-Randall rule
Statement of Van't Hoff Equation
Le-Chatelier's principle
None of these
Fugacity is a measure of the
Escaping tendencies of the same substance in different phases of a system
Relative volatility of a mixture of two miscible liquids
Behaviour of ideal gases
None of these
Internal energy of an element at 1 atm and 25° C is __________ kcal/kg.mole.
0
273
25
None of these
The minimum number of phases that can exist in a system is
0
1
2
3
Entropy of the system decreases, when
Snow melts into water
A gas expands spontaneously from high pressure to low pressure
Water is converted into ice
Both (B) & (C)
Pick out the Clausius-Clapeyron equation from the following:
dP/dT = ΔH/TΔV
ln P = - (ΔH/RT) + constant
ΔF = ΔH + T [∂(ΔF)/∂T]P
None of these
Equation which relates pressure, volume and temperature of a gas is called the
Equation of state
Gibbs Duhem equation
Ideal gas equation
None of these
Gibbs-Helmholtz equation is
ΔF = ΔH + T [∂(ΔF)/∂T]P
ΔF = ΔH - TΔT
d(E - TS) T, V < 0
dP/dT = ΔHvap/T.ΔVvap
Clapeyron Equation deals with the
Rate of change of vapour pressure with temperature
Effect of an inert gas on vapour pressure
Calculation of ΔF for spontaneous phase change
Temperature dependence of heat of phase transition
Chemical potential of ith component of a system is given by
μi = (∂F/∂ni)T, P, ni
μi = (∂A/∂ni)T, P, ni
μi = (∂F/∂ni)T, P
μi = (∂A/∂ni)T, P
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
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)
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
(∂T/∂P)H is the mathematical expression for
Specific heat at constant pressure (Cp)
Specific heat at constant volume (Cv)
Joule-Thompson co-efficient
None of these
The expression, nCv(T2 - T1), is for the __________ of an ideal gas.
Work done under adiabatic condition
Co-efficient of thermal expansion
Compressibility
None of these
Which of the following diagrams does not represent an Otto cycle?
None of these
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