Lowering of condenser temperature (keeping the evaporator temperature constant) in case of vapour compression refrigeration system results in
Increased COP
Same COP
Decreased COP
Increased or decreased COP; depending upon the type of refrigerant
Correct Answer :
A. Increased COP
Related Questions
A/an __________ system is exemplified by a vessel containing a volatile liquid in contact with its vapor.
Isolated
Closed
Open
None of these
Chemical potential is a/an
Extensive property
Intensive property
Force which drives the chemical system to equilibrium
Both (B) and (C)
With increase in pressure (above atmospheric pressure), the Cp of a gas
Increases
Decreases
Remains unchanged
First decreases and then increases
Work done is a
Property of the system
Path function
Point function
State description of a system
If the vapour pressure at two temperatures of a solid phase in equilibrium with its liquid phase are known, then the latent heat of fusion can be calculated by the
Maxwell's equation
Clausius-Clapeyron Equation
Van Laar equation
Nernst Heat Theorem
For a thermodynamic system containing 'x' chemical species, the maximum number of phases that can co-exist at equilibrium is
x
x + 1
x + 2
x + 3
The expression for entropy change given by, ΔS = - nR ln (P2/P1), holds good for
Expansion of a real gas
Reversible isothermal volume change
Heating of an ideal gas
Cooling of a real gas
A closed system is cooled reversibly from 100°C to 50°C. If no work is done on the system
its internal energy (U) decreases and its entropy (S) increases
U and S both decreases
U decreases but S is constant
U is constant but S decreases
Free energy, fugacity and activity co-efficient are all affected by change in the temperature. The fugacity co-efficient of a gas at constant pressure ____with the increase of reduced temperature.
Decreases
Increases
Remains constant
Decreases logarithmically
With increase in temperature, the internal energy of a substance
Increases
Decreases
Remains unchanged
May increase or decrease; depends on the substance
Near their critical temperatures, all gases occupy volumes __________ that of the ideal gas.
Less than
Same as
More than
Half
As the entropy of the universe is increasing, day by day, the work producing capacity of a heat engine is
Not changed
Decreasing
Increasing
Data sufficient, can't be predicted
Refrigeration cycle
Violates second law of thermodynamics
Involves transfer of heat from low temperature to high temperature
Both (A) and (B)
Neither (A) nor (B)
Heat of formation of an element in its standard state is
0
< 0
> 0
A function of pressure
One ton of refrigeration is defined as the heat rate corresponding to melting of one ton of ice in one
Hour
Day
Minute
Second
__________ explains the equilibrium constant for any chemical reaction.
Henry's law
Law of mass action
Hess's law
None of these
The number of degrees of freedom at the triple point of water is
0
1
2
3
In reactions involving solids and liquids (where change in volume is negligible), the heat of reaction at constant pressure as compared to that at constant volume is
More
Less
Same
Unpredictable; depends on the particular reaction
What happens in a reversible adiabatic compression?
Heating occurs
Cooling occurs
Pressure is constant
Temperature is constant
(1/V) (∂V/∂T)P is the mathematical expression
Joule-Thomson co-efficient
Specific heat at constant pressure (Cp)
co-efficient of thermal expansion
Specific heat at constant volume (CV)
Which of the following non-flow reversible compression processes require maximum work?
Adiabatic process
Isothermal process
Isobaric process
All require same work
The unit of fugacity is the same as that of the
Pressure
Temperature
Volume
Molar concentration
The compressibility factor of a gas is given by (where, V1 = actual volume of the gas V2 = gas volume predicted by ideal gas law)
V1/V2
V2/V1
V1 - V2
V1.V2
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
Helmholtz free energy (A) is defined as
A = H - TS
A = E - TS
A = H + TS
None of these
The standard Gibbs free energy change of a reaction depends on the equilibrium
Pressure
Temperature
Composition
All (A), (B) and (C)
In the equation, PVn = constant, if the value of n = 1, then it represents a reversible __________ process.
Isothermal
Isobaric
Polytropic
Adiabatic
An irreversible process
Is the analog of linear frictionless motion in machines
Is an idealised visualisation of behaviour of a system
Yields the maximum amount of work
Yields an amount of work less than that of a reversible process
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
Entropy, which is a measure of the disorder of a system, is:
Independent of pressure
Independent of temperature
Zero at absolute zero temperature for a perfect crystalline substance
All (A), (B) & (C)