Presentation on theme: "FARADAY’S LAW. Using Faraday’s law, solve problems related to electrolytic cells Additional KEY Terms."— Presentation transcript:

Using Faraday’s law, solve problems related to electrolytic cells Additional KEY Terms

Faraday (1791-1867) Coined terms "electrode", "anode", "cathode", "electrolyte", "ion", "anion" and "cation" Amount of product formed at each electrode is directly proportional to the amount of current passed through the cell.

I is the current in amperes (A) Q is the charge transferred in coulombs (C) t is the time in seconds (s) Current (I) 1 coulomb of charge moving per 1 second I = Q t You have to memorize this formula 1 coulomb is BILLIONS of electrons worth of charge

1 mole e - = 96 500 C 1 F = 96 500 C/mol e – Faraday (F) – the charge of 1 mole of electrons A single e - has a charge of 1.60 x 10 –19 C This is also called Faraday’s constant Summary: We can use the formula for current combined with Faraday’s constant to calculate the mass of products in an electrolytic cell

Determine the moles of electrons supplied by a battery with a current of 0.100 A for 50.0 min. Q =I · t = 0.00311 mol e - 300 C · 1 mol e – 96 500 C 0.100 · (50min x 60 sec/min) Q = 300 C

Calculate a mass of aluminum produced by 7.50 A passing through molten aluminum oxide for 6 hours, 20 minutes and 10 seconds. Al 3+ + 3e – → Al Q =I · t = 1.77 mol e - 1.71 x 10 5 C· 1 mol e – 96 500 C 7.50 A · (22810 s) Q = 1.71 x 10 5 C You will always need the formula for what your are producing – you need to know the ratio of electrons needed Once you have moles you can find mass – using molar mass

1 mol Al 27.0 g Al 1.77 mol e - 3 mol e - 1 mol Al = 15.9 g Al produced Al 3+ + 3e – → Al Use the ratio of electrons needed Every other question type is a variation of this procedure (some might give the mass and ask you to work backwards to current or time – you will always need the net ionic formula for the metal, the current formula, Faraday’s constant

CAN YOU / HAVE YOU? Using Faraday’s law, solve problems related to electrolytic cells Additional KEY Terms

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