Chemical Engineering Thermodynamics - Study Mode

[#311] __________ does not change during phase transformation processes like sublimation, melting & vaporisation.
Correct Answer

(B) Gibbs free energy

Explanation

Solution: Since during phase change the temperature and pressure remains constant we can say the gibbs free energy remains constant and the relation is given by: For single component and closed system : $$dG = VdP - SdT$$

[#312] Adiabatic compression of a saturated water vapour makes it
Correct Answer

(B) Superheated

Explanation

Solution: Adiabatic compression means no heat is allowed to transfer so $$delta Q = 0$$ xa0 by first law we can say entire compression work done is used to raise the fluid internal temperature and hence if enough work is done the saturated water temperature raises and finally reaches the superheated state.

[#313] Standard temperature and pressure (S.T.P.) is
Correct Answer

(A) 0°C and 750 mm Hg

Explanation

Solution: The S.T.P. conditions according to IUPAC is Standard Pressure = 1 atm or 750 mm Hg Standard temperature = 273.15 K or 0°C

[#314] In case of an __________ process, the temperature of the system increases.
Correct Answer

(D) Adiabatic compression

Explanation

Solution: During adiabatic compression the temperature of the gas increases because the work done on the system leads to increase in internal energy and there by increasing its temperature.

[#315] In a turbine, the fluid expands almost
Correct Answer

(C) Adiabatically

Explanation

Solution: In turbine the fluid is allowed to expand adiabatically to minimize the loss of mechanical energy in to surroundings in the form of heat so that the entire mechanical energy can be used effectively.