Chemistry 101 Chapter 9

Front 1

Chemical Energy

Back 1

Potential energy stored in chemical bonds

Front 2

Internal Energy (E)

Back 2

The sum of all the kinetic and potential energies of all of the components of a system

Front 3

Thermochemistry

Back 3

The study of the changes in energy the accompany chemical reactions

Front 4

Thermodynamics

Back 4

The study of energy and transformations

Front 5

First Law of Thermodynamics

Back 5

The principle that the energy gained or lost by a system must equal the energy lost or gained by the surroundings

Front 6

System

Back 6

The part of the universe that is the focus of a thermochemical study

Front 7

Surroundings

Back 7

Everything in a thermochemical study that is not part of the system

Front 8

State Function

Back 8

A property of an entity based solely on its chemical or physical state or both, but not on how it achieved that state

Front 9

Thermal Energy

Back 9

The portion of the total internal energy of a system that is proportional to its absolute temperature

Front 10

Exothermic Process

Back 10

One in which energy-usually in the form of heat-flows from a system into its surroundings

Front 11

Endothermic Process

Back 11

One in which energy-usually in the form of heat-flows from the surroundings into the system

Front 12

Pressure-Volume (P-V) Work

Back 12

The work associated with the expansion or compression of a gas

Front 13

Enthalpy (H)

Back 13

The sum of the internal energy and the pressure-volume product of a system; H = E + PV

Front 14

Enthalpy Change (ΔH)

Back 14

The energy absorbed by the reactants (endothermic reaction) or the energy given off by the products (exothermic reaction) for a reaction carried out at constant pressure

Front 15

Enthalpy of Fusion (ΔHfus)

Back 15

The energy required to convert 1 mole of a solid substance at its melting point into the liquid state; also called heat of fusion

Front 16

Enthalpy of Vaporization (ΔHvap)

Back 16

The energy required to convert 1 mole of a liquid substance at its boiling point into the vapor state; also called heat of vaporization

Front 17

Heat Capacity (Cp)

Back 17

The energy required to raise the temperature of an object by 1°C at constant pressure

Front 18

Specific Heat (cp)

Back 18

The energy required to raise the temperature of 1 g of a substance by 1°C at constant pressure

Front 19

Molar Heat Capacity (cp,n)

Back 19

The energy required to raise the temperature of 1 mole of a substance by 1°C at constant pressure

Front 20

Calorimetry

Back 20

The experimental determination of the quantity of energy transferred during a physical change or chemical process

Front 21

Calorimeter

Back 21

A device used to measure the absorption or release of energy by a physical change or chemical process

Front 22

Enthalpy of Reaction (ΔHrxn)

Back 22

The enthalpy change that accompanies a chemical reaction; also called heat of reaction

Front 23

Thermochemical Equation

Back 23

The chemical equation of a reaction that includes the change in enthalpy that accompanies the reaction

Front 24

Bomb Calorimeter

Back 24

A constant-volume device used to measure the energy released during a combustion reaction

Front 25

Calorimeter Constant (Ccalorimeter)

Back 25

The heat capacity of a calorimeter

Front 26

Hess's Law

Back 26

The principle that the heat of reaction ΔHrxn for a process that is the sum of two or more reactions is equal to the sum of the ΔHrxn values of the constituent reactions; also called Hess's Law of Constant Heat of Summation

Front 27

Standard Enthalpy of Reaction (ΔH°rxn)

Back 27

The enthalpy change associated with a reaction that takes place under standard conditions; also called standard heat of reaction

Front 28

Standard Conditions

Back 28

In thermodynamics: a pressure of 1 atm (~1 bar) and some specified temperature, assumed to be 25°C unless otherwise stated; for solutions, a concentration of 1 M is specified

Front 29

Standard State

Back 29

The most stable form of a substance under 1 atm pressure and some specified temperature (usually 25.0°C)

Front 30

Standard Enthalpy of Formation (ΔH°f)

Back 30

The enthalpy change of a formation reaction; also called standard heat of formation

Front 31

Formation Reaction

Back 31

A reaction in which 1 mole of a substance is formed from its component elements in their standard states

Front 32

Fuel Value

Back 32

The quantity of energy released during the complete combustion of 1 g of a substance

Front 33

Fuel Density

Back 33

The quantity of energy released during the complete combustion of a particular volume of a liquid fuel