Chemical Engineering Thermodynamics - Study Mode

[#236] High __________ is an undesirable property for a good refrigerant.
Correct Answer

(C) Viscosity

Explanation

Solution: High viscosity is obviously an undesirable property of good refrigerant as it increases the losses of energy converts the useful energy in to non-conservative frictional energy.

[#237] Chemical potential is a/an
Correct Answer

(D) Both B and C

Explanation

Solution: Chemical potential acts as a driving force or potential difference to achieve chemical equilibrium like temperature acts as a driving force or potential difference for heat transfer. Higher the potential higher is the transfer. The chemical potential when we expressed in terms of gibbs free energy it can be defined as partial molar gibbs free energy. $$mu = {left( {frac{{partial nG}}{{partial {n_j}}}}
ight)_{T,P,{n_i}}}$$ Since partial molar gibbs free energy is an intensive property chemical potential is an intensive Property.

[#238] For a real gas, the chemical potential is given by
Correct Answer

(B) RT dlnf

Explanation

Solution: We know the property relation $$dG=VdP-sdT$$ xa0 xa0 for constant temperature $$dT=0$$ For an ideal gas $$eqalign{
& dG = VdP cr
& dG = frac{{RT}}{P}dP cr
& Rightarrow dG = RTdlnP cr} $$ For a real gas also if we want to describe the relation in the same functional form we express it as $$dG = RTd ,ln, f Rightarrow dmu = RTd ,ln, f$$ xa0 xa0 xa0 where $$f=$$ fugacity, that means we buried the entire non ideality in this term fugacity. The term fugacity is also called as effective pressure.

[#239] For an ideal gas, the chemical potential is given by
Correct Answer

(A) RT dlnP

Explanation

Solution: Since for an ideal gas mixture : $$fugacity= pressure$$ [x08egin{array}{l}
dmathord{x08uildrel{lower3pthbox{$scriptscriptstylesmile$}}
over G} = RTdlnP\
Rightarrow d{mu _i} = RTdlnP
end{array}]

[#240] Boiling of liquid is accompanied with increase in the
Correct Answer

(A) Vapor pressure

Explanation

Solution: Boiling of a liquid is obviously accompanied by vapor pressure of the liquid at that temperature. Since boiling will occur when the liquid exhibited vapor pressure is equal to the external pressure imposed on that liquid.