htbruin

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I know this may seem trivial but I just want to know why is an anode is negatively charged. Since oxidation occurs at an anode, it is losing electrons. So shouldn't an anode be positively charged?

Is it negatively charged because it attracts anions?

thanks again
 

loveoforganic

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Negatively charged by convention and nothing more, IIRC. You can think of it as being negatively charged because it "repels electrons" or, in physics terms, "attracts positive charge"
 
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The anode is not negatively charged. The electrons flow to the cathode. That anodes attract anions suggests it's actually positively-charged.
 

BerkReviewTeach

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I know this may seem trivial but I just want to know why is an anode is negatively charged. Since oxidation occurs at an anode, it is losing electrons. So shouldn't an anode be positively charged?

Is it negatively charged because it attracts anions?

thanks again
This charge convention screws people up all of the time. The problem is that the sign convention for a discharging battery (like we deal with in circuits) is different from the plate charges in electrophoresis (which is a charged capacitor).

For a battery in a circuit (according to physics convention), we are told that the anode must be negative, because current is flowing to it. We are likewise told the cathode must be positive, because current is flowing from it. The reality is that it is a chemical reaction that generates the emf and there is not actual charge on either electrode. But by convention in physics, the cathode terminal of a battery is assigned a (+) and the anode terminal of a battery is assigned a (-).

For electrophoresis, the plates of a capacitor are charged as the result of an applied voltage. The electrons flow from the anode (site of oxidation: loss of electrons) to the cathode (site of reduction: gain of electrons), so the anode builds up a (+) charge over time and the cathode builds up a (-) charge over time. The electric field that is created can be filled with a viscous gel so that charged macromolecules can be separated according to their migration rate and/or migration direction through the resistive gel. Cations migrate to the cathode and anions migrate to the anode.
 

htbruin

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i guess this is one of them things you just remember. it makes sense in physics terms but not really chemistry wise.
 

Geekchick921

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I'm very comfortable with that answer too. Kind of like reduction being an increase in electrons because they say so... :)
I try not to think of it that way because they I'll get all discombobulated. I always think of reduction as it reduces the formal charge on the atom.
 

MLT2MT2DO

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i guess this is one of them things you just remember. it makes sense in physics terms but not really chemistry wise.
Why doesn't it make sense chemistry wise? An anion is a negative ion, a cation is a positive ion. An anode is negative a cathode is postive on top of this Berkeley gave a great understanding of it, what is there not to get? It becomes positive through oxidation but starts out negative
 
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htbruin

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Why doesn't it make sense chemistry wise? An anion is a negative ion, a cation is a positive ion. An anode is negative a cathode is postive on top of this Berkeley gave a great understanding of it, what is there not to get? It becomes positive through oxidation but starts out negative
well, the confusing part was "It becomes positive through oxidation but starts out negative." So the anode does become positive but they label it as negative. The anode undergoes oxidation, so chemically we would think it goes up in charge and therefore should be positively charged. the nomenclature is in reference prior to the connection of the cell then to make sense chemically imo.