Chemical Engineering Thermodynamics - Study Mode
[#146] Which of the following behaves most closely like an ideal gas?
Correct Answer
(A) He
Explanation
Solution: Helium acts more likely as ideal gas as it exists as an single atom which makes the vander waals dispersion forces as low as possible another factor is that it also consists of completely filled outer electron shell as a result, it has low tendency to react with other atoms.
[#147] The internal energy of a gas obeying P (V - b) RT (where, b is a positive constant and has a constant C v ), depends upon its
Correct Answer
(C) Temperature
Explanation
Solution: The internal energy of an gas is given by: $$eqalign{
& dU = CvdT - left[ {P + Tleft( {frac{{left( {frac{{partial V}}{{partial T}}}
ight)p}}{{left( {frac{{partial V}}{{partial P}}}
ight)T}}}
ight)dV}
ight] cr
& Rightarrow dU = CvdT + left[ {Tleft( {frac{{partial p}}{{partial {T_V}}}}
ight) - p}
ight] cr
& { ext{using the given equation:}} cr
& Pleft( {v - b}
ight) = RT cr
& Rightarrow frac{{partial P}}{{partial T}} = frac{R}{V} cr
& Rightarrow dU = {c_v}dT cr} $$ Hence internal energy is only a function of temperature.
[#148] Gibbs free energy of mixing at constant pressure and temperature is always
Correct Answer
(D) -ve
Explanation
Solution: Change of Gibbs free energy due to mixing is given as $$Delta {G_{mix}} = RTsum {} xlnx$$ xa0 xa0 since mole fraction is always less than one we can say the change due to mixing is negative.
[#149] Heating of water under atmospheric pressure is an __________ process.
Correct Answer
(B) Isobaric
Explanation
Solution: As we are heating at constant atmospheric pressure the process is isobaric.
[#150] Partial molar free energy of an element A in solution is same as its
Correct Answer
(A) Chemical potential
Explanation
Solution: The chemical potential is nothing but the partial molar Gibbs free energy. $${mu _i} = left( {frac{{partial nG}}{{partial {n_i}}}}
ight)d{n_i}$$ By which we can tell whether the chemical equilibrium is reached by a system or not.