Electrochemistry

Question 1

Steps of Balancing a Redox Reaction

Answer 1

1. Oxidation States
2. Half Reactions
3. Mass
   H2O, H+
   Basic Solution
   OH-
4. Charge
   More positive side
5. Multiply both sides of rxn
6. Add/Cancel Out
7. Verify

Question 2

Voltaic Cell

Answer 2

the electrochemical cell that produces electrical current from a spont. chemical rxn

Question 3

Electromotive Force (force that results in the motion of electrons)

Answer 3

driven by a change in potential energy between anode and cathode

Question 4

How do electrons flow?

Answer 4

From the anode (negative charged electrode) to the cathode (positive charged electrode)

Question 5

What are the potential energies for a anode and cathode?

Answer 5

High P.E. to low P.E.

Question 6

@ which site does oxdiation occur?

Answer 6

Anode

Question 7

@ which site does reduction occur

Answer 7

Cathode

Question 8

What neutralizes the charge buildup in the solution?

Answer 8

Salt Bridge

Question 9

What is used to determine Ecat and Eano?

Answer 9

Standard Hydrogen Electrode (SHE)

Question 10

What is the formula for calculating the overall cell potential?

Answer 10

Ecell = Ecat - Eano

Question 11

NIO?

Answer 11

More negative is oxidation

Question 12

PIR?

Answer 12

More positive is reduction

Question 13

Standard Potentials for Half-Rxns

Answer 13

All half reactions are written as reductions
Ecell are relative to the SHE (0.00V)
Ecell (+) = reduction is favored
Ecell (-) = reduction is not favored

Question 14

What will an oxidizing agent do to a reducing agent below it?

Answer 14

Oxidize

Question 15

What will a reducing agent do to a oxidizing agent above it?

Answer 15

Reduce

Question 16

Spontaneous Redox Rxn

Answer 16

DeltaG = negative
Ecell = positive
K > 1

Question 17

Nonspontatnoues Redox Rxn

Answer 17

DeltaG = positive
Ecell = negative
K < 1

Question 18

Delta G = -nfEcell

Answer 18

F = 96,458
n = moles of electrons

Question 19

Write the electrochemical cell notation for copper and silver.

Question 20

Draw voltaic cell

Question 21

E cell = (+)

Answer 21

Spontaneous Redox Rxn

Question 22

E cell = (-)

Answer 22

Nonspontaneous Redox Rxn

Question 23

What are the standards for CU and Ag?

Answer 23

Cu/Cu2+ potential = 0.337V
Ag/AgCl potential = 0.197V

Question 24

What acts as the electrode in a voltaic cell?

Answer 24

Metal strip (conductive surface)

Question 25

What happens to the mass of metals in a voltaic cell?

Answer 25

Mass of anode metal decreases and mass of cathode metal increases

Question 26

What charge would an electrode potential be, with a greater potential energy of an electron at that electrode?

Answer 26

The charge would be more negative because anodes (NIO) have a higher potential energy.

Question 27

Electron w/greater tendency for reduction is charged relative to SHE?

Answer 27

positive charge and positive Ecell

Question 28

Electron w/lesser tendency for reduction is charged relative to SHE?

Answer 28

negative charge and negative Ecell