Chemical Engineering Thermodynamics - Study Mode

[#71] Dry ice is
Correct Answer

(C) Solid carbon dioxide

Explanation

Solution: Dry ice is called as solid carbon dioxide. It will be below its triple point so on heating it directly gives off carbon dioxide gas.

[#72] Compressibility factor-reduced pressure plot on reduced co-ordinates facilitates
Correct Answer

(A) Use of only one graph for all gases

Explanation

Solution: The main reason behind use of the reduced properties is it converges the different plots for different gases in to one gas since different type of gases having same reduced properties behave similarly.

[#73] Entropy of a substance remains constant during a/an __________ change.
Correct Answer

(C) Reversible adiabatic

Explanation

Solution: Since only for a reversible process we have relation : $$TdS = delta Q$$ Since for an adiabatic process $$delta Q = 0$$ $$ ,,, Rightarrow $$ for an reversible adiabatic process $$TdS = 0.$$ So, entropy remains constant. Whereas for an irreversible adiabatic process $$TdS geqslant 0.$$ Hence entropy goes on increasing for an irreversible adiabatic process.

[#74] Which of the following is a thermodynamic property of a system?
Correct Answer

(D) Entropy

[#75] Pick out the undesirable property for a good refrigerant.
Correct Answer

(D) High 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.