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# Chemistry electrode potentials/oxidation states. watch

1. Hi,

I'm really unsure about how to work out which way round the equations go on charging and discharging. Is it right that on discharging the electrons go from -ve to +ve?

On the fuel cell question. I've worked out that the oxidation state of the carbon goes from +4 to -2 (so decreases by 6). The answer shows 12 electrons- is this because there are 2 molecules of CO2 produced?

Thanks
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2. (Original post by VioletPhillippo)
Hi,

I'm really unsure about how to work out which way round the equations go on charging and discharging. Is it right that on discharging the electrons go from -ve to +ve?

On the fuel cell question. I've worked out that the oxidation state of the carbon goes from +4 to -2 (so decreases by 6). The answer shows 12 electrons- is this because there are 2 molecules of CO2 produced?

Thanks
When a cell/battery is being used it is producing electricity and electrons (negative) are flowing around the external circuit.

Negative charges always flow towards positive, so, yes, when the cell is working the current flows from negative to positive around the external circuit.
3. (Original post by VioletPhillippo)
Hi,

I'm really unsure about how to work out which way round the equations go on charging and discharging. Is it right that on discharging the electrons go from -ve to +ve?

On the fuel cell question. I've worked out that the oxidation state of the carbon goes from +4 to -2 (so decreases by 6). The answer shows 12 electrons- is this because there are 2 molecules of CO2 produced?

Thanks
There are two carbon atoms in ethanol, each with an oxidation state of -2 and each turnes to oxidation state +4
4. (Original post by charco)
There are two carbon atoms in ethanol, each with an oxidation state of -2 and each turnes to oxidation state +4
Thank you

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