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15 terms

Chapter 16 Chemistry Vocabulary

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thermochemistry
is the study of changes in energy that accompany chemical reactions and physical changes
calorimetry
a device used to measure the energy as heat absorbed or released in a chemical or physical change
temperature
a measure of how hot or cold something is, specifically, a measure of the average kinetic energy of the particles in an object
joule
the unit used to express energy: equivalent to the amount of work done by a force of 1 N acting through a distance of 1 m in the direction of the force (abbreviation J)
heat
the energy transferred between objects that are different temperatures: energy is always transferred form higher-temperature objects to lower-temperature objects until thermal equilibrium is reached
specific heat
the quantity of heat required to raise a unit mass of homogenous material 1 K or 1C in a specified way given constant pressure and volume
enthalpy change
the amount of energy released or absorbed as heat by a system during a process at constant pressure
enthalpy of reaction
the amount of energy released or absorbed as heat during a chemical reaction
thermochemical equation
an equation that includes the quantity of energy released or absorbed as heat during the reaction as written
molar enthalpy of formation
the amount of energy as heat resulting from the formation of 1 mol of a substance at constant pressure
enthalpy of combustion
the energy released as heat by the complete combustion of a specific amount of a substance at constant pressure or constant volume
Hess's law
the overall enthalpy change in a reaction is equal to the sum of the enthalpy changes for the individual steps in the process
entropy
a measure of randomness or disorder of a system
free energy
the energy in a system that is available for work: a system's capacity todo useful work
free-energy change
the difference between the change in enthalpy, deltaH, and the product of the Kelvin temperature and the entropy change, which is defined as TdeltaS, at a constant pressure and temperature.