Cp - Cv = R is valid for __________ gases.
Ideal
Very high pressure
Very low temperature
All of the above
Correct Answer :
A. Ideal
Related Questions
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)
What is the value of ln y (where y = activity co-efficient) for ideal gases?
Zero
Unity
Infinity
Negative
Fugacity and pressure are numerically not equal for the gases
At low temperature and high pressure
At standard state
Both (A) and (B)
In ideal state
Isentropic process means a constant __________ process.
Enthalpy
Pressure
Entropy
None of these
In case of a reversible process (following pvn = constant), work obtained for trebling the volume (v1 = 1 m3 and v23 m3) is maximum, when the value of 'n' is
0
1
y = 1.44
1.66
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
Enthalpy changes over a constant pressure path are always zero for __________ gas.
Any
A perfect
An easily liquefiable
A real
Steam undergoes isentropic expansion in a turbine from 5000 kPa and 400°C (entropy = 6.65 kJ/kg K) to 150 kPa) (entropy of saturated liquid = 1.4336 kJ/kg. K, entropy of saturated vapour = 7.2234 kJ/kg. K) The exit condition of steam is
Superheated vapour
Partially condensed vapour with quality of 0.9
Saturated vapour
Partially condensed vapour with quality of 0.1
A solid metallic block weighing 5 kg has an initial temperature of 500°C. 40 kg of water initially at 25°C is contained in a perfectly insulated tank. The metallic block is brought into contact with water. Both of them come to equilibrium. Specific heat of block material is 0.4 kJ.kg-1. K-1. Ignoring the effect of expansion and contraction and also the heat capacity to tank, the total entropy change in kJ.kg-1, K-1 is
-1.87
0
1.26
3.91
First law of thermodynamics deals with the
Direction of energy transfer
Reversible processes only
Irreversible processes only
None of these
Joule-Thomson experiment is
Isobaric
Adiabatic
Isenthalpic
Both (B) & (C)
Near their critical temperatures, all gases occupy volumes __________ that of the ideal gas.
Less than
Same as
More than
Half
Gibbs free energy per mole for a pure substance is equal to the
Latent heat of vaporisation
Chemical potential
Molal boiling point
Heat capacity
__________ functions are exemplified by heat and work.
Path
Point
State
None of these
For a constant volume process __________ by the system is used only to increase the internal energy.
Heat absorbed
Work done
Both (A) & (B)
Neither (A) nor (B)
At a given temperature, the volume of a gas dissolved in a solvent __________ with increase in pressure.
Increases
Decreases
Remains unchanged
May increase or decrease; depends on the gas
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
For a multi-component system, the term chemical potential is equivalent to the
Molal concentration difference
Molar free energy
Partial molar free energy
Molar free energy change
A solute distributes itself between two nonmiscible solvents in contact with each other in such a way that, at a constant temperature, the ratio of its concentrations in two layers is constant, irrespective of its total amount. This is
The distribution law
Followed from Margules equation
A corollary of Henry's law
None of these
In an irreversible process
Tds = dE - dW = 0
dE - dW - Tds = 0
Tds - dE + dW < 0
Tds - dT + dW < 0
The equation Tds = dE - PdV applies to
Single phase fluid of varying composition
Single phase fluid of constant composition
Open as well as closed systems
Both (B) and (C)
Which of the following represents the Virial equation of state?
T = [RT/(V- b)] - [a/√T. V(V + b)]
PV/RT = 1 + (B/V) + (C/V2) + ……
n1u2 + μ2μ1 = 0
None of these
The temperature at which a real gas obeys the ideal gas laws over a wide range of pressure is called __________ temperature.
Boyle
Inversion
Critical
Reduced
Vapour which is at a pressure smaller than the saturation pressure for the temperature involved is called a __________ vapour.
Superheated
Desuperheated
Non-condensable
None of these
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
Pick out the wrong statement
Phase rule variables are intensive properties
Heat and work are both state function
The work done by expansion of a gas in vacuum is zero
CP and CV are state function
Entropy of an ideal gas depends upon its
Pressure
Temperature
Both (A) & (B)
Neither (A) nor (B)
Sublimation temperature of dry ice (solid CO2) is __________ °C.
-273
0
-78
5
In the reaction, represented by, 2SO2 + O2 2SO3; ΔH = - 42 kcal; the forward reaction will be favoured by
Low temperature
High pressure
Both (A) and (B)
Neither (A) nor (B)
Throttling process is a/an __________ process.
Reversible and isothermal
Irreversible and constant enthalpy
Reversible and constant entropy
Reversible and constant enthalpy