Thermodynamics

Question 1

System

Answer 1

A system is specified by a description of the material it contains and the boundaries that contain it. There are two main classifications of systems.

Question 2

Open System

Answer 2

Material may enter into or exit from the system. Many sources call this type of system a control volume.

Question 3

Closed System

Answer 3

Material may not enter into or exit from the system. Many sources call this type of system a control mass.

Question 4

Reversible process

Answer 4

A process for which there exists another process that can return the system to its original state, leaving no net effect on the system’s environment. A true reversible process cannot be achieved in practice.

The utility of investigating reversible processes is that they provide a limit to the change in state that can occur in any process.

Question 5

Irreversible Process

Answer 5

A process for which there does not exist another process that can return the system to its original state, without changing the state of the environment. All real processes are irreversible.

Question 6

Adiabatic

Answer 6

A process for which all transfers of energy occur through work interactions

Question 7

Constant property

Answer 7

A process during which the value of one property remains constant. When such a process occurs, the analysis of the process is usually simplified.

Question 8

Isometric

Answer 8

Constant-volume process (energy transfer to a closed rigid container)

Question 9

Isothermal

Answer 9

Constant-temperature process (condensation or evaporation in a heat exchanger)

Question 10

Isobaric

Answer 10

Constant-pressure process (weighted piston and cylinder)

Question 11

Isentropic

Answer 11

Constant-entropy process (ideal turbine)

Question 12

Isenthalpic

Answer 12

Constant-enthalpy process (flow through a valve)

Question 13

Clausius Statement

Answer 13

It is impossible to devise a cyclic machine that produces, as its only effect, the transfer of energy through a heat interaction from a low-temperature body to a high-temperature body

Question 14

Kelvin-Planck Statement

Answer 14

It is impossible to devise a cyclic machine that will have no other effect than to extract energy from a reservoir through a heat interaction and to produce an equal amount of energy through a work interaction.

Question 15

Gyftopolous-Baretta Statement

Answer 15

Among all possible states of system with a given value of energy and with a given set of values of the amounts of constituents and the parameters, there exists one and only one equilibrium state. Moreover, starting from any state of the system, it is possible to reach an equilibrium state with an arbitrarily specified set of values of the amounts of constituents and the parameters.