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24 terms

Chapter 16 - Energy and Chemical Change Vocabulary

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calorie
The amount of heat required to raise the temperature of one gram of pure water by one degree Celsius.
calorimeter
An insulated device that is used to measure the amount of heat released or absorbed during a physical or chemical process.
chemical potential energy
The energy stored in a substance because of its composition; is released or absorbed as heat during chemical reactions or processes.
energy
The capacity to do work or produce heat; exists as potential energy, which is stored in an object due to its composition or position, and kinetic energy, which is the energy of motion.
enthalpy
The heat content of a system at constant pressure.
enthalpy (heat) of combustion
The enthalpy change for the complete burning of one mole of a given substance.
enthalpy (heat) of reaction
The change in enthalpy for a reaction - the difference between the enthalpy of the substances that exist at the end of the reaction and the enthalpy of the substances present at the start.
entropy
A measure of the disorder or randomness of the particles of a solution.
free energy
The energy that is available to do work - the difference between the change in enthalpy and the product of the entropy change and the absolute temperature.
heat
A form of energy that flows from a warmer object to a cooler object.
Hess's Law
States that if two or more thermochemical equations can be added to produce a final equation for a reaction, the sum of the enthalpy changes for the individual reactions is the enthalpy change for the final reaction.
joule
The SI unit of heat and energy.
law of conservation of energy
States that in any chemical or physical process, energy may change from one form to another but is neither created nor destroyed.
law of disorder
States that the entropy of the universe must increase as a result of a spontaneous reaction or process.
molar enthalpy (heat) of fusion
The amount of heat required to melt one mole of a solid substance.
molar enthalpy (heat) of vaporization
The amount of heat required to evaporate one mole of a liquid.
specific heat
The amount of heat required to raise the temperature of one gram of a given substance by one degree Celsius.
spontaneous process
A physical or chemical change that occurs without outside intervention and may require energy to be supplied to begin the process.
standard enthalpy (heat) of formation
The change in enthalpy that accompanies the formation of one mole of a compound in its standard state from its constituent elements in their standard states.
surroundings
In thermochemistry, includes everything in the universe except the system.
system
In thermochemistry, the specific part of the universe containing the reaction or process being studied.
thermochemical equation
A balanced chemical equation that includes the physical states of all the reactants and products and specifies the change in enthalpy.
thermochemistry
The study of heat changes that accompany chemical reactions and phase changes.
universe
In thermochemistry, is the system plus the surroundings.