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How many coulombs are required to discharge 1 mole of the following ions: Cu^2+, Na^+,...

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arman7763 | (Level 2) Honors

Posted February 7, 2011 at 2:55 AM via web

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How many coulombs are required to discharge 1 mole of the following ions: Cu^2+, Na^+, Pb^2+.

(1 mole of electrons = 96500 coulombs)

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ndnordic | High School Teacher | (Level 2) Associate Educator

Posted February 7, 2011 at 3:01 AM (Answer #1)

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To solve this type of problem, first write the half-reaction that is taking place. Then look at the number of moles of electrons involved and then convert that to coulombs.

In the first case:

Cu =  Cu^+2 + 2 e^-1  This means that two moles of electrons are produced when copper is oxidized to copper +2.  Two moles of electrons is equal to 2 moles * 96500 Coulombs/mole = 193,000 C.

Na = Na^+1 + 1 e^-1  One mole of electrons is produced which is equal to 96,500 C

Pb = Pb ^+2  + 2 e^-1   Two moles of electrons, or 193,000 C

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