chapter 8 part 2 Flashcards

1
Q

standard reduction potentials

A

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

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2
Q

standard reduction potential

A

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

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3
Q

standard oxidation potential

A

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

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4
Q

increased potential as oxidizing agent
increased potential as reducing agent

A

increased positive value
increased negative value

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5
Q

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

A

spontaneous
nonspontaneous
equuilibrium

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6
Q

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

A

decrease until it reaches equilibrium

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7
Q

e cell potential equation

A

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

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8
Q

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

A

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

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9
Q

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

A

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

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10
Q

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

A

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

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11
Q

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

A

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

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12
Q

disproportion

A

thermodynamically spontaneous but kinetically slow
can electrochemically react with itself

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13
Q

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

A

catalysts
catalase

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14
Q

Latimer diagrams

A

a diagram that allows for a comparative investigation of REDOX potential

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15
Q

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

A

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

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16
Q

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

A

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

17
Q

Pourbaix (Eh-pH) diagrams are used to

A

study thermodynamically stable species relative to cell potential and pH

18
Q

Vertical Lines
Horizontal Lines
High Eh
Low Eh

A

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

19
Q

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

A

oxidizing conditions
reducing conditions
acidic conditions
basic conditions

20
Q

why is zinc metal attached to underground iron pipes?

A

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

21
Q

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

A

Zn-Fe alloy
ZnO forms; oxidation in air

22
Q

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

A

corrodes preferentially to the iron
more resistant to corrosion

23
Q

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

A

galvanic corrosion

24
Q

faraday’s constant

A

9.65*10^4 C/mole of electrons

25
nernst equation
corrects for temperature and concentration
26
R ideal gas constant
8.314 VC/Kmol
27
electrochemistry
study of chemical changes provided by electrical current and the production of electricity by chemical means
28
galvanic (voltanic) cell examples
spontaneous chemical reactions create electricity batteries and fuel cells
29
electrolytic cell examples
input electrical energy causes a nonspontaneous reaction to occur refining, battery charging, electroplating
30
electrode the electrode must be a
a conducting surface where the oxidation/reduction occurs conductive material. usually metallic or graphite
31
the chemical species in the half reaction are present
in each half cell