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Topic: Grade 12 pH question  (Read 2040 times)

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Offline jsid__

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Grade 12 pH question
« on: December 08, 2013, 05:00:27 PM »
My class was given a question; Given 100.0ml of 2.00mol H2SO4 mixed with 200.0ml of 0.500mol NaOH, find the pH.

Now a few of us assumed that there would be an ice table to find the [H3O+] after H2SO4 dissociates into H3O+  +  HSO4-.
Meaning to find out how much HSO4- dissociated into H3O+.
However, when we did all the calculations and thought we had an answer, our teacher said there is no ice table involved and no one was able to figure it out why not.
I attached a picture of my calculations if someone could me out with this question,

Thanks!

Offline jsid__

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Re: Grade 12 pH question
« Reply #1 on: December 08, 2013, 05:10:02 PM »
Apologies, I just realized I posted this in the wrong section

Offline Borek

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Re: Grade 12 pH question
« Reply #2 on: December 08, 2013, 05:22:25 PM »
Taking into account stoichiometry of the neutralization, after reaction solution contains just NaHSO4.

You are doing strange things with volumes, so your final results can't be right. (Volume sare not the only thing that I don't understand, you also do some strange addition when calculating concentration of H+).

I don't see anything wrong about the idea of using ICE table to calculate pH of the produced HSO4- solution, thats a sound approach that should deliver a correct result.
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Offline jsid__

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Re: Grade 12 pH question
« Reply #3 on: December 08, 2013, 05:37:39 PM »
I realized I did some incorrect switching of moles to molars, and some weird adding (as you mentioned). I'm starting from square one and I'll see if I can get it to make some more sense.

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