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") NaN 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 NaN NaN NaN NaN 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 NaN NaN NaN NaN calorimeter device used to measure the amount of heat absorbed or released in a chemical or physical process NaN NaN NaN NaN calorimetry process of measuring the amount of heat involved in a chemical or physical process NaN NaN NaN NaN chemical thermodynamics area of science that deals with the relationships between heat, work, and all forms of energy associated with chemical and physical processes NaN NaN NaN NaN endothermic process chemical reaction or physical change that absorbs heat NaN NaN NaN NaN energy capacity to supply heat or do work NaN NaN NaN NaN enthalpy (H) sum of a system’s internal energy and the mathematical product of its pressure and volume NaN NaN NaN NaN enthalpy change (ΔH) heat released or absorbed by a system under constant pressure during a chemical or physical process NaN NaN NaN NaN exothermic process chemical reaction or physical change that releases heat NaN NaN NaN NaN expansion work (pressure-volume work) work done as a system expands or contracts against external pressure NaN NaN NaN NaN 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 NaN NaN NaN NaN heat (q) transfer of thermal energy between two bodies NaN NaN NaN NaN 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) NaN NaN NaN NaN 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 NaN NaN NaN NaN hydrocarbon compound composed only of hydrogen and carbon; the major component of fossil fuels NaN NaN NaN NaN internal energy (U) total of all possible kinds of energy present in a substance or substances NaN NaN NaN NaN 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 NaN NaN NaN NaN kinetic energy energy of a moving body, in joules, equal to (where m = mass and v = velocity) NaN NaN NaN NaN nutritional calorie (Calorie) unit used for quantifying energy provided by digestion of foods, defined as 1000 cal or 1 kcal NaN NaN NaN NaN potential energy energy of a particle or system of particles derived from relative position, composition, or condition NaN NaN NaN NaN 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) NaN NaN NaN NaN standard enthalpy of combustion heat released when one mole of a compound undergoes complete combustion under standard conditions NaN NaN NaN NaN 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 NaN NaN NaN NaN 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 NaN NaN NaN NaN state function property depending only on the state of a system, and not the path taken to reach that state NaN NaN NaN NaN surroundings all matter other than the system being studied NaN NaN NaN NaN system portion of matter undergoing a chemical or physical change being studied NaN NaN NaN NaN temperature intensive property of matter that is a quantitative measure of “hotness” and “coldness” NaN NaN NaN NaN thermal energy kinetic energy associated with the random motion of atoms and molecules NaN NaN NaN NaN thermochemistry study of measuring the amount of heat absorbed or released during a chemical reaction or a physical change NaN NaN NaN NaN 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 NaN NaN NaN NaN