Electrolysis

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Electrolysis
Electrochemistry

• Chapter 17 Section 7

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Electrochemistry Electrolytic Cells

• A galvanic cell produces current spontaneous.
  positive cell potential
• An electrolytic cell uses energy to produce a
  chemical changenegative cell potential.
• Forcing a current through a cell
• cell potential is negative
• Electrical work causes a non spontaneous
  reaction to occur.
• Practice uses - recharging batteries
• producing aluminum
• plating to prevent corrosion

EXO
ENDO
p. 792
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Electrochemistry Electrolytic Cells

• Since the electrical work causes e- to flow in
  the opposite direction the anode and cathode are
  reversed.
• e- flow from anode to cathode
• The salt bridge ion flow is opposite in the two
  cells

Galvanic Cell
Electrolytic Cell
p. 817
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Electrochemistry Quantitative Electrochemistry

• Stoichiometry and Electrochemistry
• How much (g, mole, atoms) chemical change occurs
  with the flow of a given current (amps) for a
  specific time (seconds, minutes, hours)?
• Amps unit of charge 1 coulomb / 1 second
• 1 mole of e- the charge of a 1 faraday 96485
  coulomb / 1 mol e-
• The faraday is derived from the charge of an
  electron in coulombs and the number of e- in a
  mole.
• The faraday connects electricity to stoichiometry.

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Electrochemistry Quantitative Electrochemistry

• E cell potential (volts)
• Amp 1 C / 1 sec
• Volt 1 J / 1 C
• Watt 1 J / 1 second
• Volts x Amp Watt (power)
• kWh kilowatts x hours
• 1kWh 3.6 x 106 J

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Electrochemistry- Sample Page 816-817

• How much copper is plated out when 10.0 amps is
  applied for 30 minutes to the Zn Zn2 ? Cu2
  Cu cell at standard conditions?

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Electrochemistry- Sample 17.9 Page 818

• How long must a current of 5.00 A be applied to a
  solution of Ag to produce 10.5 g of solid silver?

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Electrochemistry- Sample Page 819

• Which would plate out first?

• Plating out for metals reducing
• So the metal with the highest reduction potential
  would plate out first