The temperature at which both liquid and gas phases are identical, is called the __________ point.
Critical
Triple
Freezing
Boiling
Correct Answer :
A. Critical
Related Questions
Entropy is a/an
State function
Macroscopic property
Extensive property
None of these
Translational kinetic energy of molecules of an ideal gas is proportional to (where, T = absolute temperature of the gas)
T
√T
T2
1/√T
1m3 of an ideal gas at 500 K and 1000 kPa expands reversibly to 5 times its initial volume in an insulated container. If the specific heat capacity (at constant pressure) of the gas is 21 J/mole . K, the final temperature will be
35 K
174 K
274 K
154 K
Which of the following processes cannot be made reversible even under ideal condition of operation?
Free expansion of a gas
Compression of air in a compressor
Expansion of steam in a turbine
All (A), (B) & (C)
__________ functions are exemplified by heat and work.
Path
Point
State
None of these
The partial pressure of each constituent present in an alloy is __________ the total vapor pressure exerted by the alloy.
Less than
Equal to
More than
Either (B) or (C); depends on the type of alloy
The point at which all the three (solid, liquid and gas) phases co-exist, is known as the __________ point.
Freezing
Triple
Boiling
Boyle
A chemical reaction will occur spontaneously at constant pressure and temperature, if the free energy is
Zero
Positive
Negative
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
When a gas is subjected to adiabatic expansion, it gets cooled due to
Decrease in velocity
Decrease in temperature
Decrease in kinetic energy
Energy spent in doing work
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)
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
The change in Gibbs free energy for vaporisation of a pure substance is
Positive
Negative
Zero
May be positive or negative
The ratio of equilibrium constants (Kp2/Kp1) at two different temperatures is given by
(R/ΔH) (1/T1 - 1/T2)
(ΔH/R) (1/T1 - 1/T2)
(ΔH/R) (1/T2 - 1/T1)
(1/R) (1/T1 - 1/T2)
For an irreversible process involving only pressure-volume work
(dF)T, p <0
(dF)T, p = 0
(dF)T, p > 0
(dA)T, v >0
Activity co-efficient is a measure of the
Departure from ideal solution behaviour
Departure of gas phase from ideal gas law
Vapour pressure of liquid
None of these
Pick out the wrong statement.
The values of (∂P/∂V)T and (∂2P/∂V2)T are zero for a real gas at its critical point
Heat transferred is equal to the change in the enthalpy of the system, for a constant pressure, non-flow, mechanically reversible process
Thermal efficiency of a Carnot engine depends upon the properties of the working fluid besides the source & sink temperatures
During a reversible adiabatic process, the entropy of a substance remains constant
The Carnot co-efficient of performance (COP) of a domestic air conditioner compared to a household refrigerator is
Less
More
Same
Dependent on climatic conditions
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
A gas has a volume of 27.3 c.c. at 0°C. Its volume at 10°C (if pressure remains unchanged) will be __________ c.c.
2.73
28.3
273
283
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
Partial molar free energy of an element A in solution is same as its
Chemical potential
Activity
Fugacity
Activity co-efficient
If the internal energy of an ideal gas decreases by the same amount as the work done by the system, then the
Process must be isobaric
Temperature must decrease
Process must be adiabatic
Both (B) and (C)
Which of the following is not an equation of state?
Bertholet equation
Clausius-Clapeyron equation
Beattie-Bridgeman equation
None of these
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)
During the phase transition, __________ changes.
Pressure
Volume
Temperature
All (A), (B) and (C)
With increase in temperature, the atomic heat capacities of all solid elements
Increases
Decreases
Remains unchanged
Decreases linearly
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
All gases above its inversion temperature, in a throttling process will show
A heating effect
No change in temperature
A cooling effect
Either (A) or (C)
When a system is in equilibrium for all possible processes, the differential or finite change of entropy is
< 0
> 0
= 0
None of these