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.

11 comments:

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

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    2. 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.

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    3. 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!

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    4. 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

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  2. This comment has been removed by the author.

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  3. 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!!

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    1. 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 :)

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

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  5. 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