May I ask what is Faraday's constant and why do we use it here?

asked by @myoungchulh1 • 12 months ago • Chemistry • 5 pts

Example: Gold can be plated out of a solution containing Au3+ based on the following half reaction: Au3+ (aq) + 3 e -Β  ---->Β  Au (s) a) What mass of gold is plated by a 41 minute flow of 6.8 A current? Example: Gold can be plated out of a solution containing Au3+ based on the following half reaction: Au3+ (aq) + 3 e -Β  ---->Β  Au (s) a) What mass of gold is plated by a 41 minute flow of 6.8 A current?

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The Faraday constant represents the amount of electric charge carried by one mole, or Avogadro's number, of electrons. it is measured in in coulombs per mole (C/mol).. you can get the constant from deriving it from Avogadro's number. F = (6.02 x 10 23 ) / (6.24 x 10 18 )= 9.65 x 10 4 C/mol (you need to know that but just know that the constant is equal to 9.65 x 10 4 C/mol).

Three equations relate these quantities (for you reference id you ask why i multplying by these numbers):

  • amperes x time = Coulombs (C)
  • 96,485 coulombs = 1 Faraday (F)
  • 1 Faraday = 1 mole of electrons

Au3+ (aq) + 3 e - ----> Au (s)

6.8 A * 2460 sec (41 mins) = 16728 C

16728 C * (1 Faraday / 96485 C) = 0.17337 F

0.17337 F * (1 mole e- / 1 F)= 0.17337 mole e-

0.17337 mole e- * (1 mol Au / 3 mol e-) = 0.057791 mol Au

0.057791 mol Au * (196.97 g Au / 1 mol Au) = 11.3832 g Au

answered by @angek2 • 12 months ago