The equation DU = Tds - PdV is applicable to infinitesimal changes occuring in
-
an open system of constant composition. -
a closed system of constant composition. -
an open system with changes in composition. -
a closed system with changes in composition.
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
In any spontaneous process, the __________ free energy decreases.
-
Helmholtz -
Gibbs -
both a & b -
neither 'a' nor 'b'
Which of the following is not an intensive property ?
-
Volume -
Density -
Temperature -
Pressure
Gibbs free energy per mole for a pure substance is equal to the
-
latent heat of vaporisation -
chemical potential -
molal boiling point -
heat capacity
The gas law (PV = RT) is true for an __________ change.
-
isothermal -
adiabatic -
both (a) & (b) -
neither (a) nor (b)
In case of a reversible process (following pvn = constant), work obtained for trebling the volume (v1 = 1 m3 and v2 3 m3 ) is max imum, when the value of 'n' is
-
0 -
1 -
y = 1.44 -
1.66
Heat is added at constant temperature in an ideal __________ cycle.
-
Stirling -
Brayton -
Rankine -
none of these
The unit of fugacity is the same as that of the
-
pressure -
temperature -
volume -
molar concentration
The necessary and sufficient condition for equilibrium between two phases is
-
the concentration of each component should be same in the two phases. -
the temperature of each phase should be same. -
the pressure should be same in the two phases. -
the chemical potential of each component should be same in the two phases.
Those solutions in which there is no volume change upon mixing the components in the liquid state and which, when diluted do not undergo any heat change (i.e. heat of dilution is zero), are called __________ solutions.
-
ideal -
real -
isotonic -
none of these
During a reversible isothermal expansion of an ideal gas, the entropy change is
-
+ve -
0 -
-ve -
∞
Pick out the wrong statement.
-
The values of 
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.
Pick out the correct equation relating 'F' and 'A'.
-
F = A + PV -
F = E + A -
F = A - TS -
F = A + TS
Filling of gas from a high pressure cylinder into small bottles is an example of a/an __________ process.
-
equilibrium -
adiabatic -
steady -
unsteady
__________ calorimeter is normally used for measuring the dryness fraction of steam, when it is very low.
-
Bucket -
Throttling -
Separating -
A combination of separating & throttling
In a reversible process
-
Tds = dE + dW -
dE - dW = Tds -
dW - dE = Tds -
Tds - dW + dE >0
A large iceberg melts at the base, but not at the top, because of the reason that
-
ice at the base contains impurities which lowers its melting point. -
due to the high pressure at the base, its melting point reduces. -
the iceberg remains in a warmer condition at the base. -
all (a), (b) and (c).
Consider the process A & B shown in the figure given below 
In this case, it is possilbe that
-
both the processes are adiabatic. -
both the processes are isothermal. -
process A is isothermal while B is adiabatic. -
process A is adiabatic while B is isothermal.
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.
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).