6.4 Flashcards

1
Q

What are two other words for the electrochemical cell

A

voltaic cell or galvanic cell

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2
Q

What is an electrochemical cell

A

A portable source of electricity produced by a redox reaction

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3
Q

What is the role of the salt bridge

A

make both beaker’s contents neutral to prevent electron flow to go backwards.

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4
Q

Oxidation occurs at the _____

A

anode

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5
Q

Reduction occurs at the _______

A

cathode

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6
Q

Mass of solid on the anode side will _____ as time passes

A

diminishes

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7
Q

What is a salt bridge

A

Porous barrier allowing for ion migration to counterbalance the charge of each solution.

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8
Q

What would happen with no salt bridge to counter-charge the solutions

A

a charge build-up would occur, the reduction half-cell would become negative and the oxidation half-cell would become positive. Electron flow would stop.

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9
Q

In the salt bridge, anions migrate towards the:

A

anode

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10
Q

In the salt bridge, cations migrate towards the:

A

cathode

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11
Q

When is an inverted tube used in the electrode

A

when the anode or cathode is not a solid, so you can pump gas or liquid into the solution.

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12
Q

How do you calculate the overall voltage of the cell

A

Add the half-cell potential for the reduction reaction to the inverse of the half-cell potential of the oxidation reaction

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13
Q

The combined voltage will always be ____

A

positive

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14
Q

What should you never do to the values of the reduction table

A

multiply them by any coefficient

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15
Q

What is the voltage when equilibrium is reached

A

0.00 V

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16
Q

in an electrochemical cell, the cathode is the site of

A

reduction

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17
Q

in an electrochemical cell, the anode is the site of

A

oxidation

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18
Q

electrons flow from _____ to _____

A

anode to cathode

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19
Q

In a salt bridge, anions flow to the

A

anode

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20
Q

in a salt bridge, cations flow to the

A

cathode

21
Q

How do you calculate the overall voltage of a cell

A

add the reduction voltage to the reverse of the oxidation voltage to determine the overal

22
Q

What is the most common inert

A

Pt (platinum)

23
Q

Which substances can’t act as electrodes?

A

a gas, liquid Hg, Group 1 or 2 metal

24
Q

in an electrochemical cell, the cathode is the site of

A

reduction

25
Q

in an electrochemical cell, the anode is the site of

A

oxidation

26
Q

electrons flow from _____ to _____

A

anode to cathode

27
Q

In a salt bridge, anions flow to the

A

anode

28
Q

in a salt bridge, cations flow to the

A

cathode

29
Q

How do you calculate the overall voltage of a cell

A

add the reduction voltage to the reverse of the oxidation voltage to determine the overal

30
Q

What is the most common inert

A

Pt (platinum)

31
Q

Which substances can’t act as electrodes?

A

a gas, liquid Hg, Group 1 or 2 metal

32
Q

What can be used in place of a salt bridge

A

a porous disk

33
Q

What do you call the oxidation of metals

A

corrosion

34
Q

What happens when a metal is oxidized?

A

a metal atom loses electrons to become a metal cation

35
Q

what do you call the corrosion of iron (Fe)

A

rust

36
Q

What two species are required to corrode a metal

A

oxygen and water

37
Q

What are the two regions of a water droplet

A

anode region (bottom) and cathode region (top)

38
Q

During corrosion, the metal cations move where

A

to the cathode portion of the water droplet

39
Q

What reaction takes place on the outer surface of the droplet

A

the reduction of oxygen

40
Q

What is the equation for the reduction of oxygen

A

1/2O2 (g) + H20 + 2e- => 2OH-

41
Q

Once migrated to the outer part of the drop, the metal cation joins with what?

A

joins with OH- from the reduction equation

42
Q

What are the three methods of corrosion prevention

A
  1. Isolation of metal
  2. Electrochemical principles (cathodic protection)
  3. lowering [H+]
43
Q

How does the isolation of metal work

A

By not allowing the metal to come into contact with water and oxygen

44
Q

What are some examples of the isolation of metal

A

A protective layer of paint or plastic, or attaching a tin layer to oxidize into a protective coating.

45
Q

How does cathodic protection work

A

A substance is protected from oxidation by being connected to a substance with a greater tendency to oxidize.

46
Q

What is the sacrificial anode

A

the metal with a greater tendency to oxidize used to prevent corrosion of a different metal.

47
Q

What is an example of a sacrificial anode

A

zinc

48
Q

Why does lowering the [H+] prevent corrosion

A

Because if the solution is basic it will favour the reduction of water (less water).