{"id":468,"date":"2020-06-05T11:43:09","date_gmt":"2020-06-05T15:43:09","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/thermo1\/back-matter\/glossary\/"},"modified":"2022-05-04T13:44:37","modified_gmt":"2022-05-04T17:44:37","slug":"glossary","status":"publish","type":"back-matter","link":"https:\/\/pressbooks.bccampus.ca\/thermo1\/back-matter\/glossary\/","title":{"raw":"Glossary","rendered":"Glossary"},"content":{"raw":"","rendered":"
\n
Absolute pressure<\/dfn><\/dt>\n
\n

Absolute pressure is a pressure that is measured relative to an ideal reference, or absolute vacuum. It is the sum of the atmospheric pressure and the gauge pressure. Absolute pressure is ALWAYS a positive number.<\/p>\n<\/dd>\n

Absolute temperature<\/dfn><\/dt>\n
\n

Absolute temperature, also called thermodynamic temperature, is the temperature expressed on the Kelvin<\/strong> or Rankine<\/strong> scale. Absolute zero (0 K or 0 R) is the minimum possible temperature. Matter at absolute zero is in the state of lowest possible (minimum) energy.<\/p>\n<\/dd>\n

Adiabatic process<\/dfn><\/dt>\n
\n

An adiabatic process is a process, in which heat transfer does NOT occur between a system and its surroundings.<\/p>\n<\/dd>\n

Boundary<\/dfn><\/dt>\n
\n

Boundary or system boundary refers to the surface that separates the system and its surroundings.<\/p>\n<\/dd>\n

Boundary work<\/dfn><\/dt>\n
\n

Boundary work refers to the work done by a substance at the system boundary due to the expansion or compression of the substance.<\/p>\n<\/dd>\n

Chemical equilibrium<\/dfn><\/dt>\n
\n

Chemical equilibrium is a state in which the forward and backward reactions proceed at the same rate, causing no net change of the concentrations in either the reactants or the products. A system free from chemical reactions is in chemical equilibrium.<\/p>\n<\/dd>\n

Clausius statement<\/dfn><\/dt>\n
\n

It is impossible to construct a device that operates in a cycle and produces no effect other than the transfer of heat from a lower-temperature body (heat sink) to a higher-temperature body (heat source).<\/p>\n<\/dd>\n

Closed system<\/dfn><\/dt>\n
\n

A closed system is a system of a fixed mass. Mass transfer cannot happen between a closed system and its surroundings.<\/p>\n<\/dd>\n

Constant-pressure specific heat<\/dfn><\/dt>\n
\n

Constant-pressure specific heat is a property of a substance. It equals to the amount of energy required to raise the temperature of one unit mass (i.e., 1 kg) of the substance by one degree in an isobaric process.<\/p>\n<\/dd>\n

Constant-volume specific heat<\/dfn><\/dt>\n
\n

Constant-volume specific heat is a property of a substance. It equals to the amount of energy required to raise the temperature of one unit mass of the substance by one degree in an isochoric process.<\/p>\n<\/dd>\n

Continuum<\/dfn><\/dt>\n
\n

Continuum refers to a continuous homogeneous matter distributed throughout a system.<\/p>\n<\/dd>\n

Control volume<\/dfn><\/dt>\n
\n

Control volume is also called open system. It is a selected region in space, which allows mass and energy to transfer across the boundary between the system and its surroundings.<\/p>\n<\/dd>\n

Cycle<\/dfn><\/dt>\n
\n

A cycle consists of a series of processes. The final state of a cycle is always identical to its initial state.<\/p>\n<\/dd>\n

Density<\/dfn><\/dt>\n
\n

Density is the mass per unit volume of a body or a system.<\/p>\n<\/dd>\n

Enthalpy<\/dfn><\/dt>\n
\n

Enthalpy is a thermodynamic property. It is defined as the sum of the internal energy of a system and the flow work associated with the flowing fluid.<\/p>\n<\/dd>\n

Entropy<\/dfn><\/dt>\n
\n

Entropy is a thermodynamic property, which quantifies the degree of disorder of a system resulting from the dispersal of energy and matter in a process.<\/p>\n<\/dd>\n

Equation of state<\/dfn><\/dt>\n
\n

An equation of state is an expression that relates pressure, temperature and specific volume of a gas.<\/p>\n<\/dd>\n

Equilibrium<\/dfn><\/dt>\n
\n

Equilibrium refers to a uniform condition throughout a system.<\/p>\n<\/dd>\n

Equilibrium state<\/dfn><\/dt>\n
\n

An equilibrium state refers to a state of a system in equilibrium.<\/p>\n<\/dd>\n

Extensive property<\/dfn><\/dt>\n
\n

An extensive property refers to a thermodynamic property of a system, whose magnitude depends on the mass of the system. Examples of extensive properties include mass, volume, internal energy, enthalpy, and entropy.<\/p>\n<\/dd>\n

Fusion line<\/dfn><\/dt>\n
\n

Fusion line is a curve that represents the transition between the solid and liquid phases of a substance.<\/p>\n<\/dd>\n

Heat<\/dfn><\/dt>\n
\n

Heat is a form of energy. Heat transfer will take place between two objects if they are at different temperatures.<\/p>\n<\/dd>\n

Heat engine<\/dfn><\/dt>\n
\n

Heat engine is a device that produces work by absorbing heat from a high-temperature body (heat source) and rejecting the waste heat to a low-temperature body (heat sink).<\/p>\n<\/dd>\n

Heat sink<\/dfn><\/dt>\n
\n

A heat engine, refrigerator or heat pump must operate between a high-temperature body and a low-temperature body. The low-temperature body is called heat sink.<\/p>\n<\/dd>\n

Heat source<\/dfn><\/dt>\n
\n

A heat engine, refrigerator or heat pump must operate between a high-temperature body and a low temperature body. The high-temperature body is called heat source. <\/p>\n<\/dd>\n

Ideal gas<\/dfn><\/dt>\n
\n

An ideal gas is a gas that obeys the ideal gas equation of state, Pv=RT.\u00a0<\/strong><\/em><\/p>\n<\/dd>\n

Intensive property<\/dfn><\/dt>\n
\n

An intensive property is a thermodynamic property that does not depend on the mass of a system. Examples of intensive properties include pressure, temperature, density, specific volume, specific internal energy, specific enthalpy, and specific entropy.<\/p>\n<\/dd>\n

Internal energy\u00a0<\/dfn><\/dt>\n
\n

Internal energy is a form of thermal energy. From a macroscopic level, it is strongly associated with the temperature of a system. From a microscopic level, it is associated with the motions and structure of the molecules of a system.<\/p>\n<\/dd>\n

Irreversibilities<\/dfn><\/dt>\n
\n

Irreversibilities refer to factors that render a process irreversible.<\/p>\n<\/dd>\n

Isentropic process<\/dfn><\/dt>\n
\n

An isentropic process refers to a process that is reversible and adiabatic. The entropy remains constant in an isentropic process.<\/p>\n<\/dd>\n

Isobaric process<\/dfn><\/dt>\n
\n

An isobaric process refers to a process whose pressure remains constant.<\/p>\n<\/dd>\n

Isochoric process<\/dfn><\/dt>\n
\n

An isochoric process refers to a process of constant specific volume.<\/p>\n<\/dd>\n

Isolated system<\/dfn><\/dt>\n
\n

An isolated system cannot exchange mass or energy with its surroundings.<\/p>\n<\/dd>\n

Isothermal process<\/dfn><\/dt>\n
\n

An isothermal process refers to a process whose temperature remains constant.<\/p>\n<\/dd>\n

Kelvin-Planck Statement<\/dfn><\/dt>\n
\n

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.<\/p>\n<\/dd>\n

Mechanical equilibrium<\/dfn><\/dt>\n
\n

Mechanical equilibrium refers to an equilibrium condition, in which the pressure of a system has no tendency to change over time.<\/p>\n<\/dd>\n

Open system<\/dfn><\/dt>\n
\n

Open system is also called control volume. It is a selected region in space, which allows mass and energy to transfer across the boundary between the system and its surroundings.<\/p>\n<\/dd>\n

Phase diagram<\/dfn><\/dt>\n
\n

Phase diagram is a graphical representation of a substance's state (solid, liquid or vapour) under different conditions of temperature and pressure.<\/p>\n<\/dd>\n

Phase equilibrium<\/dfn><\/dt>\n
\n

Phase equilibrium is an equilibrium condition. For a system consisting of a mixture of multiple phases, if the composition of the mixture remains constant over time, the system is in phase equilibrium.<\/p>\n<\/dd>\n

Pressure<\/dfn><\/dt>\n
\n

Pressure is the normal force exerted by an object on a surface per unit area of the surface.<\/p>\n<\/dd>\n

Process<\/dfn><\/dt>\n
\n

A process refers to the change in a system from one state to another state.<\/p>\n<\/dd>\n

Pure substance<\/dfn><\/dt>\n
\n

A pure substance refers to a matter that has a homogeneous and definite chemical composition. A pure substance may exist in a single phase or as a multi-phase mixture.<\/p>\n<\/dd>\n

Quasi-equilibrium process<\/dfn><\/dt>\n
\n

A quasi-equilibrium process refers to a process, in which all states are equilibrium states.<\/p>\n<\/dd>\n

Real gas<\/dfn><\/dt>\n
\n

A real gas refers to a gas, whose pressure, temperate and specific volume behaviour cannot be represented by the ideal gas equation of state.<\/p>\n<\/dd>\n

Reversible process<\/dfn><\/dt>\n
\n

A reversible process refers to a process that can be reversed without leaving any changes in either the system or its surroundings. In a reversible process, both the system and its surroundings can always return to their original states.<\/p>\n<\/dd>\n

Single phase<\/dfn><\/dt>\n
\n

Single phase refers to the solid, liquid or vapour (or gaseous) phase that a substance exists at a certain condition.<\/p>\n<\/dd>\n

Specific boundary work<\/dfn><\/dt>\n
\n

Specific boundary work is the boundary work done by one unit mass of a substance.<\/p>\n<\/dd>\n

Specific enthalpy<\/dfn><\/dt>\n
\n

Specific enthalpy is the enthalpy per unit mass of a system.<\/p>\n<\/dd>\n

Specific entropy<\/dfn><\/dt>\n
\n

Specific entropy is the entropy per unit mass of a system.<\/p>\n<\/dd>\n

Specific heat<\/dfn><\/dt>\n
\n

Specific heat, also called heat capacity, is a thermodynamic property to quantify the energy storage capacity of a substance. It is defined as the amount of heat required to raise the temperature of one unit mass of a substance by one degree.<\/p>\n<\/dd>\n

Specific internal energy<\/dfn><\/dt>\n
\n

Specific internal energy is the internal energy per unit mass of a system.<\/p>\n<\/dd>\n

Specific property<\/dfn><\/dt>\n
\n

A specific property is the corresponding extensive property per unit mass. Examples of specific properties include specific volume, specific internal energy, specific enthalpy, and specific entropy. Specific properties are intensive properties.<\/p>\n<\/dd>\n

Specific volume<\/dfn><\/dt>\n
\n

Specific volume is the volume per unit mass of a system. It is the reciprocal of density.<\/p>\n<\/dd>\n

State<\/dfn><\/dt>\n
\n

A state refers to a specific condition of a system that is described by a unique set of thermodynamic properties, such as pressure, temperature, specific volume, specific enthalpy, and so on.<\/p>\n<\/dd>\n

Steady flow<\/dfn><\/dt>\n
\n

A steady flow through a control volume refers to a flow, in which the properties, such as the mass and energy of the control volume remain unchanged over time.<\/p>\n<\/dd>\n

Sublimation line<\/dfn><\/dt>\n
\n

The sublimation line is the curve that represents the transition between the solid and vapour phases of a substance in a phase diagram.<\/p>\n<\/dd>\n

Surroundings<\/dfn><\/dt>\n
\n

In thermodynamic analysis, the universe is divided into two parts: a system and its surroundings. Surroundings refer to the rest of the universe outside of the system.<\/p>\n<\/dd>\n

System<\/dfn><\/dt>\n
\n

In thermodynamic analysis, the universe is divided into two parts: a system and its surroundings. A system refers to a selected quantity of matter or a region in space.<\/p>\n<\/dd>\n

Temperature<\/dfn><\/dt>\n
\n

Temperature is a measurable thermodynamic property that indicates the hotness or coldness of a body.<\/p>\n<\/dd>\n

Thermal equilibrium<\/dfn><\/dt>\n
\n

Thermal equilibrium is an equilibrium condition. A system in thermal equilibrium has a uniform temperature everywhere.<\/p>\n<\/dd>\n

Thermodynamics<\/dfn><\/dt>\n
\n

Thermodynamics is a branch of science. It originally focused on the scientific theories of heat-work conversion, and the operations and efficiency improvement of heat engines. Nowadays, the applications of thermodynamics have extended to all fields related to energy conversion and conservation.<\/p>\n<\/dd>\n

Transient flow<\/dfn><\/dt>\n
\n

A transient flow refers to a flow through a control volume, in which the properties, such as the mass and energy of the control volume change over time.<\/p>\n<\/dd>\n

Triple point<\/dfn><\/dt>\n
\n

The triple point refers to a unique state of a substance, at which the three phases, solid, liquid and vapour, coexist in equilibrium.<\/p>\n<\/dd>\n

Vapourization line<\/dfn><\/dt>\n
\n

The vapourization line refers to the curve that represents the transition between the liquid and vapour phases of a substance in a phase diagram.<\/p>\n<\/dd>\n

Work<\/dfn><\/dt>\n
\n

Work is a form of energy that is transferred to or from a body by applying a force on that body along a displacement.<\/p>\n<\/dd>\n<\/dl>\n","protected":false},"author":1076,"menu_order":8,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"back-matter-type":[37],"contributor":[59,60],"license":[],"class_list":["post-468","back-matter","type-back-matter","status-publish","hentry","back-matter-type-glossary","contributor-amanda-grey","contributor-erin-fields"],"_links":{"self":[{"href":"https:\/\/pressbooks.bccampus.ca\/thermo1\/wp-json\/pressbooks\/v2\/back-matter\/468","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.bccampus.ca\/thermo1\/wp-json\/pressbooks\/v2\/back-matter"}],"about":[{"href":"https:\/\/pressbooks.bccampus.ca\/thermo1\/wp-json\/wp\/v2\/types\/back-matter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/thermo1\/wp-json\/wp\/v2\/users\/1076"}],"version-history":[{"count":4,"href":"https:\/\/pressbooks.bccampus.ca\/thermo1\/wp-json\/pressbooks\/v2\/back-matter\/468\/revisions"}],"predecessor-version":[{"id":604,"href":"https:\/\/pressbooks.bccampus.ca\/thermo1\/wp-json\/pressbooks\/v2\/back-matter\/468\/revisions\/604"}],"metadata":[{"href":"https:\/\/pressbooks.bccampus.ca\/thermo1\/wp-json\/pressbooks\/v2\/back-matter\/468\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.bccampus.ca\/thermo1\/wp-json\/wp\/v2\/media?parent=468"}],"wp:term":[{"taxonomy":"back-matter-type","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/thermo1\/wp-json\/pressbooks\/v2\/back-matter-type?post=468"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/thermo1\/wp-json\/wp\/v2\/contributor?post=468"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/thermo1\/wp-json\/wp\/v2\/license?post=468"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}