5.4: Key Terms
- Page ID
- 415169
\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)
| Words (or words that have the same definition) | The definition is case sensitive | (Optional) Image to display with the definition [Not displayed in Glossary, only in pop-up on pages] | (Optional) Caption for Image | (Optional) External or Internal Link | (Optional) Source for Definition |
|---|---|---|---|---|---|
| (Eg. "Genetic, Hereditary, DNA ...") | (Eg. "Relating to genes or heredity") |  | The infamous double helix | https://bio.libretexts.org/ | CC-BY-SA; Delmar Larsen |
| Word(s) | Definition | Image | Caption | Link | Source |
|---|---|---|---|---|---|
| bomb calorimeter | device designed to measure the energy change for processes occurring under conditions of constant volume; commonly used for reactions involving solid and gaseous reactants or products | ||||
| calorie (cal) | unit of heat or other energy; the amount of energy required to raise 1 gram of water by 1 degree Celsius; 1 cal is defined as 4.184 J | ||||
| calorimeter | device used to measure the amount of heat absorbed or released in a chemical or physical process | ||||
| calorimetry | process of measuring the amount of heat involved in a chemical or physical process | ||||
| chemical thermodynamics | area of science that deals with the relationships between heat, work, and all forms of energy associated with chemical and physical processes | ||||
| endothermic process | chemical reaction or physical change that absorbs heat | ||||
| energy | capacity to supply heat or do work | ||||
| enthalpy (H) | sum of a system’s internal energy and the mathematical product of its pressure and volume | ||||
| enthalpy change (ΔH) | heat released or absorbed by a system under constant pressure during a chemical or physical process | ||||
| exothermic process | chemical reaction or physical change that releases heat | ||||
| expansion work (pressure-volume work) | work done as a system expands or contracts against external pressure | ||||
| first law of thermodynamics | internal energy of a system changes due to heat flow in or out of the system or work done on or by the system | ||||
| heat (q) | transfer of thermal energy between two bodies | ||||
| heat capacity (C) | extensive property of a body of matter that represents the quantity of heat required to increase its temperature by 1 degree Celsius (or 1 kelvin) | ||||
| Hess’s law | if a process can be represented as the sum of several steps, the enthalpy change of the process equals the sum of the enthalpy changes of the steps | ||||
| hydrocarbon | compound composed only of hydrogen and carbon; the major component of fossil fuels | ||||
| internal energy (U) | total of all possible kinds of energy present in a substance or substances | ||||
| joule (J) | SI unit of energy; 1 joule is the kinetic energy of an object with a mass of 2 kilograms moving with a velocity of 1 meter per second, 1 J = 1 kg m2/s and 4.184 J = 1 cal | ||||
| kinetic energy | energy of a moving body, in joules, equal to (where m = mass and v = velocity) | ||||
| nutritional calorie (Calorie) | unit used for quantifying energy provided by digestion of foods, defined as 1000 cal or 1 kcal | ||||
| potential energy | energy of a particle or system of particles derived from relative position, composition, or condition | ||||
| specific heat capacity (c) | intensive property of a substance that represents the quantity of heat required to raise the temperature of 1 gram of the substance by 1 degree Celsius (or 1 kelvin) | ||||
| standard enthalpy of combustion | heat released when one mole of a compound undergoes complete combustion under standard conditions | ||||
| standard enthalpy of formation | enthalpy change of a chemical reaction in which 1 mole of a pure substance is formed from its elements in their most stable states under standard state conditions | ||||
| standard state | set of physical conditions as accepted as common reference conditions for reporting thermodynamic properties; 1 bar of pressure, and solutions at 1 molar concentrations, usually at a temperature of 298.15 K | ||||
| state function | property depending only on the state of a system, and not the path taken to reach that state | ||||
| surroundings | all matter other than the system being studied | ||||
| system | portion of matter undergoing a chemical or physical change being studied | ||||
| temperature | intensive property of matter that is a quantitative measure of “hotness” and “coldness” | ||||
| thermal energy | kinetic energy associated with the random motion of atoms and molecules | ||||
| thermochemistry | study of measuring the amount of heat absorbed or released during a chemical reaction or a physical change | ||||
| work (w) | energy transfer due to changes in external, macroscopic variables such as pressure and volume; or causing matter to move against an opposing force |