General Chemistry Ch 7. Thermochemistry

Question 1

Isolated systems

Answer 1

Exchange neither matter nor energy with the environment

Question 2

Closed systems

Answer 2

Can exchange energy but not matter with the environment

Question 3

Open systems

Answer 3

Can exchanged both energy and matter with the environment

Question 4

Isothermal processes

Answer 4

Occur at a constant temperature

Question 5

Adiabatic processes

Answer 5

Exchange no heat with the environment

Question 6

Isobaric processes

Answer 6

Occur at a constant pressure

Question 7

Isovolumetric/Isochoric processes

Answer 7

Occur at a constant volume

Question 8

State functions

Answer 8

Describe the physical properties of an equilibrium state, they are pathway independent and include pressure, density, temperature, volume, enthalpy, internal energy, Gibbs free energy, and entropy

Question 9

Standard conditions

Answer 9

298K, 1atm, and 1M concentrations

Question 10

Standard state

Answer 10

The most prevalent form of an element under standard conditions, where standard enthalpy, standard entropy, and standard free energy are calculated

Question 11

Phase changes

Answer 11

Exist at characteristic temperatures and pressures

Question 12

Fusion

Answer 12

aka melting, occurs at the boundary between the solid and the liquid phases

Question 13

Freezing

Answer 13

aka crystallization or solidification, occurs at the boundary between the solid and the liquid phases

Question 14

Vaporization

Answer 14

aka evaporation or boiling, occurs at the boundary between the liquid and gas phases

Question 15

Condensation

Answer 15

Occurs at the boundary between the liquid and the gas phases

Question 16

Sublimation and deposition

Answer 16

Occur at the boundary between the solid and gas phases

Question 17

Critical point

Answer 17

If the temperature is above this point, the liquid and gas phases are indistinguishable

Question 18

Triple point

Answer 18

Point where all three phases of matter exist in equilibrium

Question 19

Phase diagram

Answer 19

Graphs the phases and phase equilibria as a function of temperature and pressure

Question 20

Temperature

Answer 20

Scaled measure of the average kinetic energy of a substance

Question 21

Heat

Answer 21

The transfer of energy that results from differences of temperature between two substances, the heat content of a system undergoing heating, cooling, or phase changes is the sum of all the respective energy changes

Question 22

Enthalpy

Answer 22

Measure of the potential energy of a system found in intermolecular attractions and chemical bonds, can also be calculated using heats of formation, heats of combustion, or bond dissociation energies

Question 23

Hess’s law

Answer 23

States that the total change in potential energy of a system is equal to the changes of potential energies of the individual steps of the process

Question 24

Entropy

Answer 24

A measure of the degree to which energy has been spread throughout a system or between a system and its surroundings, ratio of heat transferred per mole per unit K, maximized at equilibrium

Question 25

Gibbs free energy

Answer 25

Derived from both enthalpy and entropy values for a given system, change in Gibbs free energy determines whether a process is spontaneous or non spontaneous, depends on temperature meaning temperature dependent processes change between spontaneous and non spontaneous depending on the temp

Question 26

DeltaG <0

Answer 26

Reaction proceeds in the forward direction (spontaneous)

Question 27

DeltaG=0

Answer 27

Reaction is in dynamic equilibrium

Question 28

DeltaG>0

Answer 28

Reaction proceeds in reverse direction (non spontaneous)