Definitions

Question 1

Define equilibrium

Answer 1

A state of system where no net force or heat flow exists.

Question 2

Define enthalphy

Answer 2

The total heat content of a system - a combination of microscopic internal energy and macroscopic flow work

Question 3

Define property

Answer 3

A value that can be used to define an equilibrium.

Question 4

What is a thermodynamic temperature scale?

Answer 4

A scale of temperature measurement that is independent of any substance’s thermometric properties, and which has an absolute zero.

Question 5

What is the Clausius statement of the Second Law?

Answer 5

“It is impossible to construct a machine which in itself will cause thermal energy to pass from a cold reservoir to a hot reservoir”

Question 6

Define polytropic process

Answer 6

A process for which it is viable to relate pressure and volume as pVⁿ = constant, where n is a given constant for a particular process

Question 7

Define cyclic process

Answer 7

A process that always returns to the same equilibrium over the course of its operation

Question 8

Define reversible process

Answer 8

A process that can be reversed without leaving any trace on its surroundings

Question 9

What is the state postulate?

Answer 9

Equilibrium is specified if two independent intensive properties of the system are know

Question 10

Define closed system (control mass)

Answer 10

A system of fixed mass which allows only energy transfers at its boundary i.e. which does not allow mass transfer at its boundary

Question 11

Define open system (control volume)

Answer 11

A fixed region of space, for which both matter and energy may cross its boundary

Question 12

Define intensive property

Answer 12

A property that is independent of the amount of matter within the system

Question 13

Define extensive property

Answer 13

A property that is dependent upon the quantity of matter within the system

Question 14

Define adiabatic

Answer 14

Involves no heat transfer

Question 15

Define process

Answer 15

A system’s change from one equilibrium state to another

Question 16

Define path

Answer 16

The series of states that a system passes through over the course of a process

Question 17

Define quasi-equilibrium process

Answer 17

A process that is sufficiently slow such that the system undergoing it is able to adjust without any part of said system having any property different from another part within the system

Question 18

Define isothermal

Answer 18

Constant temperature

Question 19

Define isobaric

Answer 19

Constant pressure

Question 20

Define isochoric/isometric

Answer 20

Constant volume

Question 21

Define isentropic

Answer 21

Constant entropy

Question 22

Define a steady-flow process

Answer 22

A process during which fluid flows through a control volume steadily

Question 23

What is the Zeroth Law?

Answer 23

If two bodies are in thermal equilibrium with a third body, then they are also in thermal equilibrium with each other

Question 24

What is heat?

Answer 24

The form of energy that is transferred between two systems as a consequence of a temperature difference

Question 25

What is heat flow?

Answer 25

Transfer of thermal energy

Question 26

What is the First Law?

Answer 26

Energy can be neither created nor destroyed, it can merely change form

Question 27

What is the Kelvin-Planck statement of the Second Law?

Answer 27

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

Question 28

Define system

Answer 28

A quantity of matter or region of space selected for analysis

Question 29

What is the Carnot efficiency?

Answer 29

The maximum efficiency a heat engine operating between two thermal reservoirs can have

Question 30

Define internal energy

Answer 30

The sum of all forms of microscopic energy - a property of state that follows from the first corollary of the first law

Question 31

Define entropy

Answer 31

A property of state that indicates a system’s degree of organisation and irreversibility (if that system is thermally isolated)