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    I have been doing past paper questions and find that there are different cell diagrams. One with platinum, one with hydrogen, one with just metal on either sides on the electrodes.

    What is the difference and when they ask me to draw one how do I know which one to draw?! Electrochemical cells are used as power sources in many everyday applications. To decide what to use in a cell, it is necessary to know the standard electrode potential for electrodes. This is measured using a standard hydrogen electrode as a reference standard.
    Draw a labelled diagram of the apparatus you would use to measure the standard electrode potential of an Fe3+ / Fe2+ electrode.

    In the marks scheme is has H2 gas etc... so how do i know to draw that one and how do I even draw that one?! :/
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    (Original post by aladdin818)
    I have been doing past paper questions and find that there are different cell diagrams. One with platinum, one with hydrogen, one with just metal on either sides on the electrodes.

    What is the difference and when they ask me to draw one how do I know which one to draw?! Electrochemical cells are used as power sources in many everyday applications. To decide what to use in a cell, it is necessary to know the standard electrode potential for electrodes. This is measured using a standard hydrogen electrode as a reference standard.
    Draw a labelled diagram of the apparatus you would use to measure the standard electrode potential of an Fe3+ / Fe2+ electrode.

    In the marks scheme is has H2 gas etc... so how do i know to draw that one and how do I even draw that one?! :/
    Because the standard hydrogen electrode is always used to measure the standard electrode potential of a half cell. It's to the left.

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    (Original post by Kvothe the arcane)
    Because the standard hydrogen electrode is always used to measure the standard electrode potential of a half cell. It's to the left.

    ah cheers But do you know what would be on the right hand side? It says Fe2+ and Fe3+ and there should be another platinum electrode. So, would both Fe2+ and Fe2+ be the solution that the Pt is dissolved in?
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    (Original post by aladdin818)
    ah cheers But do you know what would be on the right hand side? It says Fe2+ and Fe3+ and there should be another platinum electrode. So, would both Fe2+ and Fe2+ be the solution that the Pt is dissolved in?
    Pt isn't dissolved. It's a solid which is the surface on which the ions are reacted. The solution will be an equimolar mix of fe2+ and fe3+ ions at 1moldm-3

    Sent from my SM-G925F using Tapatalk
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    (Original post by Kvothe the arcane)
    Pt isn't dissolved. It's a solid which is the surface on which the ions are reacted. The solution will be an equimolar mix of fe2+ and fe3+ ions at 1moldm-3

    Sent from my SM-G925F using Tapatalk
    I hate to be a pain, but this is all new and I'm trying to understand it, When I label Fe 2+ and Fe3+ do I label it as 'Fe2+, Fe3+' as the solution in the next electrode. Sorry for bugging :/ thanks for your time!
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    You aren't being a pain! Does the image above help?
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    (Original post by Kvothe the arcane)


    You aren't being a pain! Does the image above help?
    OHHH I understand thank you so much! Cleared up all my confusion ahah
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    (Original post by aladdin818)
    OHHH I understand thank you so much! Cleared up all my confusion ahah
    No worries

    The setup is the same for other solution half cells. Just remember all your labels!
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    Hi, could anyone tell me why the Pt electrode is generally drawn so small in the S.H.E.? It often looks like the wire attached to the Pt electrode is submerged in the solution, which surely isn't correct as then the wire would act as the electrode. Sorry, maybe this is irrelevant anyway, I'm just confused about how to draw it in an exam - should the Pt be entirely submerged in the solution or have the top half above the soln like usual?
 
 
 

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