Cell Stoichiometry

  • Thread starter Nope
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  • #1
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Homework Statement



Determine the mass of sodium deposited at the cathode of a molten NaCl(l) electrolytic cell if 10.0 A flow through the cell for 2.00h.

Homework Equations





The Attempt at a Solution


For the mole ratio,
Na+ +e --> Na
2Cl- --> Cl2 + 2e
Should I balance the electron ? 2Na+ +2e --> 2Na
or I use Na+ +e --> Na
Thanks
 

Answers and Replies

  • #2
Borek
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Na+ + e- -> Na will do.

Do you know Farady's law of electrolysis? Do you know how to calculate charge given current and time?

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  • #3
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Yes.
But when should I balance the electron?
 
  • #4
Borek
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Not sure what you mean - sodium reduction reaction is written is already balanced.

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  • #5
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You balance the half equations, Then identify which is oxidised and reduced, then you add the electrons to the specific sides (RHS reduction, LHS oxidisation). but if Na+(aq) + e- --> Na(s).

Just check your standard reduction potentials chart and you'll see.
 
  • #6
Borek
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Na+(aq) + e- --> Na(s).

Na+(aq) + e- -> Na(s) - state of matter symbol should be listed in plain text, not subscript nor anything.

Just check your standard reduction potentials chart and you'll see.

These are of no use here - you are already told what is the reaction that goes on - reduction of sodium.

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methods
 
Last edited:
  • #7
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The super script was an accident, But I dont see why i cannot use sub script for them?
 
  • #8
Borek
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See http://www.iupac.org/reports/provisional/abstract05/GreenBook051206_prs.pdf [Broken], General Chemistry section, Other symbols and conventions in chemistry (2.10.1), (vi) States of aggregation.

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methods
 
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  • #10
Borek
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You don't have to - we are interested only in sodium and we need just sodium half reaction. Balanced - but half reaction only.

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