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Topic: pH?  (Read 14289 times)

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Offline Borek

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Re: pH?
« Reply #15 on: September 01, 2006, 05:30:43 PM »
What is the pH of a solution with [H+] = 6 x 10-6?

Can someone just please tell me what the pH of this is???

I think its 5.22, but I'm wrong.

You are calculating it right, although you may be using too much significant figures in your answer.
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Offline Shea

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Re: pH?
« Reply #16 on: September 01, 2006, 06:03:30 PM »
Really?  I told my teacher that I used a calculator, and did it the same way as they show in my book, but she said, "I assure you, it's incorrect."

Should I just say 5.2?

Offline Borek

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Re: pH?
« Reply #17 on: September 01, 2006, 06:19:07 PM »
Really?  I told my teacher that I used a calculator, and did it the same way as they show in my book, but she said, "I assure you, it's incorrect."

Should I just say 5.2?

Or even 5. As long as you have not missed something. What is exact wording of the question?
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Offline Shea

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Re: pH?
« Reply #18 on: September 01, 2006, 06:23:40 PM »
That is the exact wording.

Offline english

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Re: pH?
« Reply #19 on: September 01, 2006, 08:22:43 PM »
Don't forget that pH is a measure of the acidity/basicity of a solution.

pKa/pKb is a measure of the acidity/basicity of a compound.

Offline Shea

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Re: pH?
« Reply #20 on: September 06, 2006, 04:30:40 PM »
How would I find the pH of a 0.6M solution of NH3?

I am utterly perplexed by this question.  :-\

Offline Borek

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Re: pH?
« Reply #21 on: September 06, 2006, 04:43:58 PM »
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Offline Donaldson Tan

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Re: pH?
« Reply #22 on: September 13, 2006, 09:29:50 AM »
How would I find the pH of a 0.6M solution of NH3?

pH = 14 - pOH
pOH = - lg [ OH- ]

NH3 (aq) + H2O (l) <-> NH4+ (aq) + OH- (aq)

Kb = [ NH4+ ] [ OH- ] / [ NH3 ]

let concentration of OH- be x (unit M)
Kb = x2/(0.6 - x)
This is a quadratic expression. Solve for x.

pOH = - lg x
pH = 14 - pOH = 14 + lg x
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