Chemistry Flash Cards For Thermodynamic Chapter 15

Front 1

Absolute entropy of a substance

Back 1

the entropy of a substance relative to its entropy in a perfectly ordered crystalline form at 0 K

Front 2

Bomb Calorimeter

Back 2

A device used to measure the heat transfer between system and surroundings at constant volume

Front 3

Bond Energy

Back 3

the amount of energy necessary to break one mole of bonds in a gaseous substance, to form gaseous products at the same temperature and pressure

Front 4

Calorimeter

Back 4

a device used to measure the heat transfer that accompanies a physical or chemical change

Front 5

endothermic process

Back 5

a process that absorbs heat

Front 6

enthalpy change, change in H

Back 6

the quantity of heat transferred into or out of a system as it undergoes a chemical or physical change at constant temperature and pressure

Front 7

entropy, S

Back 7

A thermodynamic state property that measures the degree of disorder or randomness of a system

Front 8

equilibrium

Back 8

a state of dynamic balance in which the rates of forward and reverse processes(reactions) are equal; the state of a system which neither the forward nor the reverse process is thermodynamically favored.

Front 9

Exothermic process

Back 9

a process that gives off(releases) heat

Front 10

First Law of Thermodynamics

Back 10

the total amount of energy in the universe is constant(also known as the Law of Conservation of Energy); energy is neither created nor destroyed in ordinary chemical reactions and physical changes.

Front 11

Gibbs free energy, G

Back 11

The thermodynamic state function of a stystem that indicates the amount of energy available for the system to do tuseful work at constant T and P. It is defined as G= H-TS

Front 12

Gibbs free energy change, change in G

Back 12

the indicator of spontaneity of a process at constant T and P. Change in G= change in H - T times the change in S. If the change in G is negative, the process is product-favored(spontaneous).

Front 13

Hess's Law of Heat Summation

Back 13

The enthalpy change for a reaction is the same wheter it occurs in one step or a series of steps.

Front 14

Internal Energy, E

Back 14

All forms of energy associated with a specific amount of a substance

Front 15

Law of Conservation of Energy

Back 15

Energy cannon be created or destroyed in a chemical reaction or in a physical change; it may be changed from one form to another. See first law of thermodynamics

Front 16

Mole of reaction( mol rxn)

Back 16

the amount of reaction that corresponds to the number of moles of each substance shown in the balanced equation

Front 17

Nonspontaneous change

Back 17

reactant-favored change

Front 18

pressure-volume work

Back 18

work done by a gas when it expands against an external pressure or work done on a system as gases are compressed or consumed in the presence of an external pressure

Front 19

Product-favored change

Back 19

a change for which the collection of products is more stable than the collection of reactants under the given conditions; also called spontaneous change

Front 20

reactant-favored change

Back 20

a change for which the collection of reactants is more stable than the collection of preoducts under the given conditionsl; also called nonspontaneous change.

Front 21

Second Law of Thermodynamics

Back 21

the universe tends toward a state of greater disorder in spontaneous processes

Front 22

Spontaneous change

Back 22

see product-favored change

Front 23

Standard enthalpy change, change in H^0

Back 23

the enthalpy change in which the number of moles of reactants specirfied in the balanced chemical equation, all at standard states, is converted completely to the specified number of moles of products, all at standard states, is converted completely to the specified number of moles of products, all at standard states

Front 24

Standard entropy change, change in S^0

Back 24

Teh entropy change in which the number of moles of reactants specified in the balanced chemical equation, all at standard states, is converted completely to the specified number of moles of products, all at standard states.

Front 25

Standard molar enthalpy of formation, change in H^0, f subscript(of a substance)

Back 25

the enthalpy change for the formation of one mole of a substance in a specified state from its elements in their standard states; also called standard molar heat of formation or just heat of formation.

Front 26

Standard molar entropy, S^0(of a substance)

Back 26

The absolute entropy of a substance in its standard state at 298 K

Front 27

Standard reacton

Back 27

a reaction in which the numbers of moles of reactants shown in the balanced equation, all in their standard states, are completely converted to the numbers of moles of products shown in the balanced equation, also all at their standard states.

Front 28

Standard state( of a substance)

Back 28

See thermodynamic state of a substance

Front 29

State function

Back 29

a variable that defines the state of a system; a function that is independent of the pathway be which a process occurs

Front 30

Surroundings

Back 30

Everythin in the environment of the system

Front 31

Stystem

Back 31

the substances of interest in a process; the part of the universe under investigation

Front 32

Thermochemical equation

Back 32

a balanced chemical equation together with a designation of the corresponding value of change in H reaction. Sometimes used with chagnes in other thermodynamic quantities

Front 33

Thermochemistry

Back 33

the observation, measurement, and prediction of energy changes for both physical changes and ch emical reactions

Front 34

Thermodynamics

Back 34

the study of the energy transfers accompanying physical and chemical processes

Front 35

Thermodynamic state of a system

Back 35

a set of conditions that completely specifies all of the properties of the system

Front 36

Thermodynamic standard state of a substance

Back 36

The most stable state of the substance at one atmosphere pressure and at some specific temperature(25 degress celsius unless otherwise specified).

Front 37

Third Law of Thermodynamics

Back 37

the entropy of a hypothetical pure, perfect, crystalline substance at absolute zer temperature is zero

Front 38

Universe

Back 38

the system plus the surroundings

Front 39

Work

Back 39

the application of a force through a distance; for physical changes r chemical reactions at constant external pressure, the work done on the system is -P change in V; for chemical reactions that involve gases, the work done on the system can be expressed as -(change in n)RT.