Chemical Engineering Thermodynamics - Study Mode

[#216] For a constant pressure reversible process, the enthalpy change (ΔH) of the system is
Correct Answer

(C) ∫C p .dT

Explanation

Solution: By the definition of $${C_P}$$ we can write $${C_P} = mathop {lim }limits_{delta T o 0} {left( {frac{{delta Q}}{{delta T}}}
ight)_P}.$$ Under constant pressure process, and by first law of thermodynamics $$Q = dH.$$ $$eqalign{
& Rightarrow {left( {frac{{partial H}}{{partial T}}}
ight)_P} = {C_P} cr
& Rightarrow Delta H = int {{C_P}.dT} cr} $$

[#217] In an ideal gas mixture, fugacity of a species is equal to its
Correct Answer

(B) Partial pressure

Explanation

Solution: Fugacity for ideal gas mixture is equal to its partial pressure but for a real gas mixture it is not equal to partial pressure higher the difference between fugacity and partial pressure higher is the non-ideality actually the fugacity coefficient acts as a measure of non-ideality.

[#218] Critical temperature is defined as the temperature above which a gas will
Correct Answer

(C) Never liquify however high the pressure may be

Explanation

Solution: Since at or above critical state there is no strong demarcation between the vapor and liquid that means the properties doesn’t show any abrupt changes the gas can’t be liquefied.

[#219] Equation which relates pressure, volume and temperature of a gas is called the
Correct Answer

(A) Equation of state

Explanation

Solution: We know that the equation which relates the easily measurable and sensible properties (basic properties of a substance) nothing but the temperature, pressure and volume is called equation of state.

[#220] A chemical reaction will occur spontaneously at constant pressure and temperature, if the free energy is
Correct Answer

(C) Negative

Explanation

Solution: Since for an spontaneous process $$TdS > dU + PdV$$ For, constant temperature and constant pressure process the above equation can be written as $$eqalign{
& dleft( {TS - U}
ight) > PdV cr
& Rightarrow dleft( { - A}
ight) > PdV cr
& Rightarrow {left( {dG}
ight)_{T,P}} < 0 cr} $$ For spontaneous process.