Bertybassett
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Hi, I have a few chemistry questions. Firstly, when you right an expression including the partial pressures of an equation, do you write p or pp? e.g. if cl2 was present, would we write(pCl2) or (ppCl2)? Two different markschemes for aqa have given one as p and another as pp ? Also, is the positive electrode the one where reduction is occurring? Also, I dont understand that if the cathode is negative, why is it the electrode where reduction occurs? Many thanks
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sunnyun
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I would say write p(Cl2) instead of pp(Cl2), that is what OCR uses but either way, I don't think you would be penalised for either.

Reduction is the gain of electrons, which happens at the positive electrode so oxidation (the loss of electrons) happens at the negative electrode.
I tend to not think using the terms cathode and anode because they just confuse me as it is the opposite (I think) to what I learned about electrolysis at GCSE, so instead just use positive and negative electrode.
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Bertybassett
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ah ok thanks
(Original post by sunnyun)
I would say write p(Cl2) instead of pp(Cl2), that is what OCR uses but either way, I don't think you would be penalised for either.

Reduction is the gain of electrons, which happens at the positive electrode so oxidation (the loss of electrons) happens at the negative electrode.
I tend to not think using the terms cathode and anode because they just confuse me as it is the opposite (I think) to what I learned about electrolysis at GCSE, so instead just use positive and negative electrode.
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Pigster
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(Original post by Bertybassett)
Hi, I have a few chemistry questions. Firstly, when you right an expression including the partial pressures of an equation, do you write p or pp? e.g. if cl2 was present, would we write(pCl2) or (ppCl2)? Two different markschemes for aqa have given one as p and another as pp ? Also, is the positive electrode the one where reduction is occurring? Also, I dont understand that if the cathode is negative, why is it the electrode where reduction occurs? Many thanks
p or pp, matters not. What does matter is to make sure you avoid square brackets.

The name cathode and anode and their correspondence to +ve and -ve electrode depends on whether you are generating electricity or using electricity. As sunnyun said, why not just stick to +ve and -ve electrodes. Surely no exam board (these days) will give a mark for requiring you to remember the name of an electrode.
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