Chapter 17

Question 1

spontaneous process

Answer 1

occur without ongoing outside intervention

Question 2

when ice melts, water evaporates, or salt dissolves in water

Answer 2

the arrangement of molecules or ions becomes more disorderly.

Question 3

second law

Answer 3

for any spontaneous process, the entropy of the universe increases (ΔSuniv > 0)

“Entropy of the universe is increasing.”

Question 4

Know that the entropy of matter increases as it changes state from

Answer 4

solid to liquid to gas

Question 5

Any spontaneous process is _____

Answer 5

irreversible!

Question 6

thermodynamics predicts

Answer 6

whether a process will proceed under given conditions

Question 7

entropy

Answer 7

a thermodynamic function that increases as the number of energetically equivalent ways of arranging the components increases.

Question 8

positional entropy (why do gases expand in a vacuum?)

Answer 8

A gas expands into a vacuum because the expanded state has the highest positional probability of states available to the system.

Question 9

Entropies of complex molecules are less than or greater than those of simple molecules.

Answer 9

greater

Question 10

Entropy change is favorable when…

Answer 10

in a more random system

Question 11

Entropies of solutions are greater than or less than those of pure liquids and solids.

Answer 11

greater

Question 12

The Third Law of Thermodynamics

Answer 12

for a perfect crystal at absolute zero, the absolute entropy = 0 J/mol K.

Question 13

Gibbs free energy

Answer 13

is the maximum amount of work energy that can be released to the surroundings by a system

Question 14

first law

Answer 14

Energy is conserved.

Question 15

standard entropy depends on…

Answer 15

the number of “places” to put that energy, including the state of the substance, the molar mass, the particular allotrope, the molecular complexity, and the extent of dissolution.

Question 16

reversible reaction

Answer 16

one that will change direction upon an infinitesimally small change in a variable (i.e., temperature or pressure) related to the reaction. All real reactions are irreversible and do not achieve the theoretical limit of free energy.

Question 17

reducing agent

Answer 17

what is getting oxidized

Question 18

oxidizing agent

Answer 18

what is getting reduced

Question 19

paired redox reactions are carried out in an…

Answer 19

ectrochemical cell (a.k.a. voltaic or galvanic cell).
These cells can generate an electrical current.

Question 20

electrolytic cells use electrical current to…

Answer 20

drive nonspontaneous chemical reactions.

Question 21

electrochemical reactions are a combination of…

Answer 21

half-cell reactions—oxidation occurring at an anode, and reduction occurring at a cathode.

Question 22

components of a voltaic cell

Answer 22

half-cells, electrodes, salt bridge, and the potential difference generated.

Question 23

oxidation–reduction reactions mean that

Answer 23

electrons are transferred from one atom to another

Question 24

Oxidation: one or more of these processes occur

Answer 24

the oxidation number of an element increases
an element loses electrons
a compound gains oxygen
a compound loses hydrogen
a half-reaction has electrons as products

Question 25

Reduction: one or more of these processes occur

Answer 25

the oxidation number of an element decreases an element gains electrons a compound loses oxygen a compound gains hydrogen a half-reaction has electrons as reactants

Question 26

Oxidation (Anode or Cathode)

Answer 26

Anode

Question 27

Reduction (Anode or Cathode)

Answer 27

Cathode

Question 28

electrons will flow from

Answer 28

the electrode in the less concentrated solution to the electrode in the more concentrated solution.

Question 29

Electrolysis

Answer 29

the process of using electricity to break apart a compound.