Redox Reactions and Electrochemistry

Question 1

electrochemical cells

Answer 1

contained systems where redox reactions occur

Question 2

galvanic cells

Answer 2

• voltaic cells
• spontaneous reactions (-deltaG)
• supply energy and are used to do work
• oxidation and reduction half reactions are placed in half cells connected by an apparatus that allows for electron transfer
• negative anode
• EMF is positive (favorable)

Question 3

electrolytic cells

Answer 3

• nonspontaneous reaction (+deltaG)
• electrical energy in required to induce a reaction
• amount of chemical change induces is directly proportional to the number of moles of electrons that are exchanged during a redox reaction
• positive anode
• EMF is negative (not favorable)

Question 4

Faraday’s constant

Answer 4

• the amount of charge contained in one mols of electrons

- F = 96,487 coulombs or J/V

Question 5

balancing redox reactions

Answer 5

1. separate 2 half reactions
2. balance all atoms except O and H
3. acidic solutions-use H2O to balance O atoms and H+ to balance H atoms
   basic solutions-use OH- to balance O atoms and H2O to balance H atoms
4. balance the charges of each half reaction with electrons
5. reduction and oxidation half reactions must have the same number of electrons

Question 6

the mass of an element produced at the cathode or anode of an electrolytic cell varies:

Answer 6

directly with current