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Iodine Clock help

I'm doing the iodine clock with hydrogen peroxide.
i know that in respect with I the order is first, in respect to H202 its first. However for H+ ions, im not sure whether its first or zero. ive read several different things, and now i'm just so confussssed:confused:
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Original post by Izar
I'm doing the iodine clock with hydrogen peroxide.
i know that in respect with I the order is first, in respect to H202 its first. However for H+ ions, im not sure whether its first or zero. ive read several different things, and now i'm just so confussssed:confused:


It's zero order for H+
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Izar
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Original post by ZakRob
It's zero order for H+


i got first order :frown:
how can i tell from a half-life graph that its zeroth order? because for a first order, the half lives remain constant..
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Original post by Izar
i got first order :frown:
how can i tell from a half-life graph that its zeroth order? because for a first order, the half lives remain constant..


Is this not for the iodine clock, whereby you'd be timing how long it takes for a colour change to occur. and that would be time, t. then to calculate initial rate of reaction, you would simply use 1/t which is proportional to initial rate of reaction.

Then when you plot that on a graph you should get a constant horizontal line.

However for concentration against time graphs look at the image attached, it has examples shown.
(edited 11 years ago)
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Izar
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Original post by ZakRob
Is this not for the iodine clock, whereby you'd be timing how long it takes for a colour change to occur. and that would be time, t. then to calculate initial rate of reaction, you would simply use 1/t which is proportional to initial rate of reaction.

Then when you plot that on a graph you should get a constant horizontal line.

However for concentration against time graphs look at the image attached, it has examples shown.



Original post by ZakRob


ahh that means all my data and graphs are wrong for the H+, btw how do you know its zeroth order?
and thank you so much, i actually understand it now <3
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Original post by Izar
ahh that means all my data and graphs are wrong for the H+, btw how do you know its zeroth order?
and thank you so much, i actually understand it now <3


I only know its zeroth order from a task that I did in chemistry regarding this reaction.
It should be zero order :smile:
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Izar
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Original post by ZakRob
I only know its zeroth order from a task that I did in chemistry regarding this reaction.



Original post by grassgrazers01
It should be zero order :smile:


Thank you guys <3
@grassgrazers have you done the coursework? :biggrin:
Original post by Izar
Thank you guys <3
@grassgrazers have you done the coursework? :biggrin:


I've done the iodine clock using different chemicals, but a friend of mine did it with hydrogen peroxide. He experimentally found the order of H+ ions to be zeroth, and this was later confirmed by my teacher :smile:
Original post by grassgrazers01
It should be zero order :smile:


Indeed, it is a Harcourt-Essen reaction and should hold zero order :smile:
The reaction needs H+ ions to acidify it and thus reduce the H2O2.
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Izar
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Original post by grassgrazers01
I've done the iodine clock using different chemicals, but a friend of mine did it with hydrogen peroxide. He experimentally found the order of H+ ions to be zeroth, and this was later confirmed by my teacher :smile:



Original post by Chunnikan Smudge
Indeed, it is a Harcourt-Essen reaction and should hold zero order :smile:
The reaction needs H+ ions to acidify it and thus reduce the H2O2.


So can i just check... its first order for H2O2 and I , but zero order for H+?
thanks guys :')
Original post by Izar
So can i just check... its first order for H2O2 and I , but zero order for H+?
thanks guys :')


Yes, thats correct for all :smile:
Original post by Izar
So can i just check... its first order for H2O2 and I , but zero order for H+?
thanks guys :')


Yes indeedy :3
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Original post by grassgrazers01
Yes indeedy :3


thank you pumpkin :hugs:

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