Electrolysis Chapter 17 Section 7 Electrochemistry e-

Electrochemistry – Electrolytic Cells A galvanic cell produces current spontaneous. positive cell potential An electrolytic cell uses energy to produce a chemical change negative 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 e- EXO ENDO p. 792

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 e- Galvanic CellElectrolytic Cell p. 817

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= 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. e- all about negative charge, electronsabout any charge negative or positive x C x mol e-

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 10 6 J e-

Electrochemistry- Sample Page How much copper is plated out when 10.0 amps is applied for 30 minutes to the Zn ǀ Zn 2+ ǁ Cu 2+ ǀ Cu cell at standard conditions?

e- 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?

e- 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