During Joule-Thomson expansion of gases
Enthalpy remains constant
Entropy remains constant
Temperature remains constant
None of these
Correct Answer :
A. Enthalpy remains constant
Related Questions
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)
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)
The intensive properties are
Molar volume, density, viscosity and boiling point
Refractive index and surface tension
Both (A) and (B)
None of these
In which of the following reaction equilibrium, the value of equilibrium constant Kp will be more than is Kc?
2HI H2 + I2
N2O4 2NO2
2SO2 + O2 2SO3
None of these
What is the degree of freedom for two miscible (non-reacting) substances in vapor-liquid equilibrium forming an azeotrope?
0
1
2
3
Which of the following is not an intensive property?
Molar heat capacity
Internal energy
Viscosity
None of these
At absolute zero temperature, the __________ of the gas is zero.
Pressure
Volume
Mass
None of these
For a real gas, the chemical potential is given by
RT d ln P
RT d ln f
R d ln f
None of these
__________ decreases during adiabatic throttling of a perfect gas.
Entropy
Temperature
Enthalpy
Pressure
The expression for the work done for a reversible polytropic process can be used to obtain the expression for work done for all processes, except reversible __________ process.
Isobaric
Isothermal
Adiabatic
None of these
Solubility of a substance which dissolves with an increase in volume and liberation of heat will be favoured by the
Low pressure and high temperature
Low pressure and low temperature
High pressure and low temperature
High pressure and high temperature
Normal temperature and pressure (N.T.P.) corresponds to
0°C and 760 mm Hg
15°C and 760 mm Hg
20°C and 760 mm Hg
0°C and 1 kgf/cm2
Pick out the wrong statement.
An ideal liquid or solid solution is defined as one in which each component obeys Raoult's law
If Raoult's law is applied to one component of a binary mixture; Henry's law or Raoult's law is applied to the other component also
Henry's law is rigorously correct in the limit of infinite dilution
None of these
During a reversible isothermal expansion of an ideal gas, the entropy change is
+ve
0
-ve
∞
Critical compressibility factor for all substances
Are more or less constant (vary from 0.2 to 0.3)
Vary as square of the absolute temperature
Vary as square of the absolute pressure
None of these
What is the degree of freedom for a system comprising liquid water equilibrium with its vapour?
0
1
2
3
__________ increases with increase in pressure.
The melting point of wax
The boiling point of a liquid
Both (A) and (B)
Neither (A) nor (B)
No work is done by the system, when a reaction occurs at constant
Volume
Temperature
Pressure
None of these
Degree of freedom of the system ice-watervapour will be
0
1
2
3
Specific __________ does not change during a phase change (e.g. sublimation, melting, vaporisation etc.).
Entropy
Internal energy
Enthalpy
Gibbs free energy
Heat requirement for decomposition of a compound into its elements is __________ that is evolved during the formation of that compound from its elements.
The same
Less than
Greater than
Different than
If we increase the pressure on a substance (which is at its triple point), then the triple point
Increases
Decreases
Remains unchanged
May increase or decrease; depends on the substance
When a system is in equilibrium for all possible processes, the differential or finite change of entropy is
< 0
> 0
= 0
None of these
What is the value of ln y (where y = activity co-efficient) for ideal gases?
Zero
Unity
Infinity
Negative
Number of phases in a colloidal system is:
1
2
3
4
What happens in a reversible adiabatic expansion process?
Heating takes place
Cooling takes place
Pressure is constant
Temperature is constant
After throttling, gas temperature
Decreases
Increases
Remain same
May increase or decrease; depends on the nature of the gas
Throttling process is a/an __________ process.
Reversible and isothermal
Irreversible and constant enthalpy
Reversible and constant entropy
Reversible and constant enthalpy
Tea kept in a thermos flask is vigorously shaken. If the tea is considered as a system, then its temperature will
Increase
Decrease
Remain unchanged
First fall and then rise
Joule-Thomson co-efficient is defined as
μ = (∂P/∂T)H
μ = (∂T/∂P)H
μ = (∂E/∂T)H
μ = (∂E/∂P)H