Sunday, 28 April 2013

1.55 write ionic half-equations representing the reactions at the electrodes during electrolysis

At the positive electrode, electrons will be lost: to show this we write the lost electrons as products:
2Br- > Br2 + 2e-
Make sure the charges are equal on both sides: 1- > 1-.

At the negative electrode, electrons will be gained so we write them as reactants:
2H+ + 2e- > H2
And to make sure the charges are the same on both sides: 0 > 0.
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12 comments:

  1. MyLongNameIsBetterThanYourLongName6 January 2014 at 00:34

    Hi, just a very small point, I think the equation at the anode should be 2Br- ---> 2Br + 2e- :) Thanks for all the notes btw, they're really really helpful!!! :)

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    Replies
    1. HannahHelp22 February 2014 at 07:38

      Ah, yeah, thank you! Have changed that!
      It's ok :)

      Delete
    2. Anonymous28 December 2014 at 05:43

      I think you might have been right the first time, I use BrINClHOF to determine if the element is found naturally in pairs and Bromine is one of them, this could mean Br2 was right? Obviously I am just trying to make this already brilliant revision checklist better for everyone, rather than starting a meaningless argument.

      Delete
    3. HannahHelp17 June 2015 at 15:35

      Oh yes you are right Fellow Saturn... I guesse I will change it back again hahaha, probably end up changing it a third time ;)
      Thanks for the help!

      Delete
    4. HannahHelp17 June 2015 at 15:38

      Oh wait, I think its because it makes it look like one bromine with a negative charge of two, not sure how its meant to be written so I will just leave it like that but if anyone is confused they can just have a nice little read of this haha

      Delete
  2. Unknown7 January 2015 at 12:04

    This comment has been removed by the author.

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  3. Unknown7 June 2015 at 11:01

    Thanks sooo much for this blog it is the best revision source ever!!!! (now my school recommend it)
    Hope your exams go really well for you!!

    ReplyDelete
    Replies
    1. HannahHelp17 June 2015 at 15:39

      Hahaha that's a big compliment, thank you :) Oh that's cool, give everyone best wishes for results day!
      So do I! Haha, and you too :)

      Delete
  4. Unknown15 February 2016 at 03:36

    Hannah can I ask what you got in IGCSE bio, chem and phys?

    I'm sure it was 3 A*s well at least I think you deserve it!

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    Replies
    1. Tabby M21 March 2016 at 16:03

      yup she said she got 3 A*'s in each science (bio, chem & phys)

      Delete
  5. Unknown15 February 2016 at 03:37

    Hannah can I ask what you got in IGCSE bio, chem and phys?

    I'm sure it was 3 A*s well at least I think you deserve it!

    ReplyDelete
  6. Unknown1 January 2018 at 01:35

    can we have the other half equations for the other compounds

    ReplyDelete

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