ENTHALPY

Question 1

is the reaction with oxygen to produce small molecules such as CO2 and H2O

Answer 1

Combustion

Question 2

liquid to solid

Answer 2

freezing

Question 3

gas to liquid

Answer 3

condensation

Question 4

gas to solid

Answer 4

deposition

Question 5

Exothermic Processes

Answer 5

Combustion
Phase Changes: Freezing, Condensation, Deposition
Dissolution
Bond Formation
Electron Gain

Question 6

two unstable atoms may form a stable molecule

Answer 6

Bond Formation

Question 7

some ionic compounds that dissociate into ions in water release energy

Answer 7

Dissolution

Question 8

electron affinity is the energy released when a gaseous atom accepts an electron

Answer 8

Electron Gain

Question 9

these processes are accompanied by lowering of the temperature (cooling) of the surroundings

Answer 9

Endothermic Process

Question 10

this can sometimes be endothermic

Answer 10

Dissolution

Question 11

Endothermic Process

Answer 11

• Phase Changes: Fusion, Vaporization, Sublimation
• Bond Dissociation
• Ionization

Question 12

solid to liquid

Answer 12

fusion

Question 13

liquid to gas

Answer 13

vaporization

Question 14

solid to gas

Answer 14

sublimation

Question 15

is the energy needed to break a bond joining two atoms

Answer 15

bind dissociation energy

Question 16

is the energy needed to remove an electron from a gaseous atom

Answer 16

Ionization Energy

Question 17

are process that release heat to surroundings

Answer 17

Exothermic processes

Question 18

are processes that absorb heat from the surroundings

Answer 18

Endothermic Processes

Question 19

is the sum of the internal energy (E) and the product of work at constant PRESSURE

Answer 19

Enthalpy

Question 20

is the expansion and compression of the system, therefore it is brought upon the change in PRESSURE and VOLUME

Answer 20

Work

Question 21

at constant pressure, enthalpy of a process is equal to the ________

Answer 21

Heat (q)

Question 22

is the difference between the enthalpies of product and enthalpies of reactants

Answer 22

enthalpy of reaction

Question 23

enthalpy change of solid to liquid

Answer 23

enthalpy of reaction
enthalpy of fusion

Question 24

enthalpy change of phase 1 to phase 2

Answer 24

enthalpy of translation

Question 25

enthalpy change of liquid to gas

Answer 25

enthalpy of vaporization

Question 26

enthalpy change of solid to gas

Answer 26

enthalpy of sublimation

Question 27

enthalpy change of solute to solution

Answer 27

enthalpy of solution

Question 28

enthalpy change of elements to compound

Answer 28

enthalpy of formation

Question 29

enthalpy change of compound

Answer 29

enthalpy of combustion

Question 30

delta H < 0 (negative value)

Answer 30

exothermic

Question 31

delta H > 0 (positive value)

Answer 31

endothermic

Question 32

is an extensive property (depends on the amount of substance involved in a process)

Answer 32

Enthalpy Change

Question 33

is the enthalpy change accompanying a process undergone by 1 mole of a substance

Answer 33

Molar Enthalpy Change

Question 34

is the physical state of a pure substance in its most stable form at 1 atm and 25 degrees celsius

Answer 34

thermodynamic standard state

Question 35

is the enthalpy change involved in the formation of 1 mole of a substance from elements in their standard states

Answer 35

standard enthalpy of formation of standard heat of formation

Question 36

is the enthalpy change involved in a chemical reaction at standard conditions (1 atm and 25 degrees celsius)

Answer 36

standard enthalpy of reaction of standard heat of reaction

Question 37

is it equal to the sum of the standard heats of formation of products less the sum of the standard heats of formation of reactants

Answer 37

standard enthalpy of reaction of standard heat of reaction

Question 38

is the sum of internal energy and the product of pressure and volume

Answer 38

enthalpy of a system

Question 39

is equal to heat at constant pressure. It gives us an idea whether the process is exothermic or endothermic

Answer 39

enthalpy of a process

Question 40

is a chemical equation that indicates the energy, particularly the heat of enthalpy change, that accompanies the reaction

Answer 40

thermochemical equation

Question 41

for an exothermic reaction, the sign of the standard heat of reaction is _________

Answer 41

negative

Question 42

for an endothermic reaction, the sign of the standard heat of reaction is ________

Answer 42

positive

Question 43

is the sum of the enthalpy changes of all steps leading to this reaction

Answer 43

enthalpy of a reaction

Question 44

change in enthalpy of a chemical reaction depends upon the initial and final state of a chemical reaction irrespective of the number of steps involved in a chemical reaction

Answer 44

Hess's Law

Question 45

this law states that the enthalpy of a reaction is the sum of the enthalpy changes of the steps leading to this reaction

Answer 45

Hess Law