chapter 8 part 2

Question 1

standard reduction potentials

Answer 1

standard state: 1.0 M, 1.0 atm, 25 degrees Celsius

Question 2

standard reduction potential

Answer 2

the driving force of the reduction half-reaction
reduction potential is a positive value

Question 3

standard oxidation potential

Answer 3

the driving force of the oxidation half-reaction
oxidation is the reverse of reduction, therefore, oxidation potential is a negative value

Question 4

increased potential as oxidizing agent
increased potential as reducing agent

Answer 4

increased positive value
increased negative value

Question 5

if cell potential is positive, the reaction is
if cell potential is negative, the reaction is
if cell potential is 0, the reaction is

Answer 5

spontaneous
nonspontaneous
equuilibrium

Question 6

as a spontaneous reaction occurs, it will leave standard state and e cell potential will

Answer 6

decrease until it reaches equilibrium

Question 7

e cell potential equation

Answer 7

e cell 0 = -e cell reduction (oxidation) + e cell reduction 0

Question 8

would it be wise to store 1.0 M KMnO4 in an iron storage tank at 25 degrees storage?

Answer 8

No, a spontaneous REDOX reaction occurs between the permanganate and the solid iron container. the storage tank would corrode

Question 9

what metals can be oxidized by Al3+ cations under standard conditions?
reduction e cell = -1.66 V

Answer 9

any metals with an oxidation potential > +1.66 V will form a (+) e cell potential
Na or Li. the aluminum will reduce to Al0 and the metals will oxidize to +1

Question 10

what will happen when you put Cu metals in AgNO3 solution?

Answer 10

a strip of Cu metal placed in AgNO3 solution will result in silver metal and copper nitrate solution

Question 11

rusting of iron in aqueous solution,
the iron (II) hydroxide is reasonably
Fe(OH)2 is rapidly oxidized by

Answer 11

Fe0 is readily oxidized to Fe2+
soluble in water
oxygen to Fe2O3

Question 12

disproportion

Answer 12

thermodynamically spontaneous but kinetically slow
can electrochemically react with itself

Question 13

kinetics can be influenced by
your body uses the enzyme ? to remove dangerous peroxides

Answer 13

catalysts
catalase

Question 14

Latimer diagrams

Answer 14

a diagram that allows for a comparative investigation of REDOX potential

Question 15

electrochemical products of rusting are
why does rusting occur faster near oceans or where roads are salted?

Answer 15

Fe(OH)2 and Fe(OH)3
the ionic conductivity of the water promotes flow of electrons

Question 16

in well oxygenated water, the ultimate product is
in poorly oxygenated water, the ultimate product is

Answer 16

Fe2O3 and FeO(OH) (can form rusticles)
Fe3O4

Question 17

Pourbaix (Eh-pH) diagrams are used to

Answer 17

study thermodynamically stable species relative to cell potential and pH

Question 18

Vertical Lines
Horizontal Lines
High Eh
Low Eh

Answer 18

equilibrium independent of potential
equilibrium solely dependent on potential. independent of pH
oxidized species
reduced species

Question 19

towards top
towards bottom
ph 0-7
pH 7-14

Answer 19

oxidizing conditions
reducing conditions
acidic conditions
basic conditions

Question 20

why is zinc metal attached to underground iron pipes?

Answer 20

the O2 will oxidize the zinc metal over iron metal. once all zinc is oxidized, the O2 will begin to oxidize the iron

Question 21

iron is dipped into molten zinc. the zinc diffuses into the outer Fe-layers forming a
a dense non-conducting surface of ? forms. preventing ?

Answer 21

Zn-Fe alloy
ZnO forms; oxidation in air

Question 22

if ZnO layer is penetrated, the zinc
galvanization of iron makes the object

Answer 22

corrodes preferentially to the iron
more resistant to corrosion

Question 23

an electrochemical process in which one metal corrodes preferentially to another when both metals are in electrical contact, in the presence of an electrolyte

Answer 23

galvanic corrosion

Question 24

faraday’s constant

Answer 24

9.65*10^4 C/mole of electrons

Question 25

nernst equation

Answer 25

corrects for temperature and concentration

Question 26

R ideal gas constant

Answer 26

8.314 VC/Kmol

Question 27

electrochemistry

Answer 27

study of chemical changes provided by electrical current and the production of electricity by chemical means

Question 28

galvanic (voltanic) cell
examples

Answer 28

spontaneous chemical reactions create electricity
batteries and fuel cells

Question 29

electrolytic cell
examples

Answer 29

input electrical energy causes a nonspontaneous reaction to occur
refining, battery charging, electroplating

Question 30

electrode
the electrode must be a

Answer 30

a conducting surface where the oxidation/reduction occurs
conductive material. usually metallic or graphite

Question 31

the chemical species in the half reaction are present

Answer 31

in each half cell