Thermodynamics

Question 1

It is impossible to construct a device that operates in a cycle that produces no effect other than the transfer of heat from a lower temperature body to a higher temperature body.

Answer 1

Clausius Statement

Question 2

It is impossible for any device that operates on a cycle to receive heat from a single reservoir and produce a net amount of work.

Answer 2

Kelvin-Plank Statement

Question 3

What is the value of the work done for a closed, reversible, isometric system?

Answer 3

In an isometric process, the volume remains constant. Since work done 𝑊 = 𝑃 Δ 𝑉 W=PΔV, and Δ 𝑉 = 0 ΔV=0 in this case:

Work done = 0

Question 4

The property which expresses the work potential of the energy contained in a system at a specified state is called…

Answer 4

The property is called the availability or exergy. It quantifies the maximum useful work obtainable as a system interacts with its environment until equilibrium is reached. Answer: Availability (Exergy)

Question 5

The entropy change for any closed system which undergoes an adiabatic process…

Answer 5

For an adiabatic process, no heat transfer occurs (Q=0). The entropy change depends on whether the process is reversible or irreversible: If the process is reversible, the entropy change is: ΔS=0 If the process is irreversible, the entropy increases due to irreversibilities (e.g., friction, unrestrained expansion): ΔS>0
Answer:
0 for a reversible adiabatic process.
Positive ( Δ 𝑆 > 0 ΔS>0) for an irreversible adiabatic process.