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Topic: Calculate pH values  (Read 2708 times)

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Offline CoCoCo

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Calculate pH values
« on: November 24, 2012, 06:59:07 PM »
1. A solution with a hydrogen ion (H+) concentration of 1x10^-4 M

2. A solution with a hydroxide ion (OH-) concentration of 1x10^-6 M

I understand that 1 is an acid and 2 is a base. I just need help getting started.

Offline Borek

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Re: Calculate pH values
« Reply #1 on: November 25, 2012, 04:11:03 AM »
First is just a matter of applying the definition. Second is a matter of knowing what are pH and pOH and how they are related.
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Offline CoCoCo

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Re: Calculate pH values
« Reply #2 on: November 25, 2012, 10:16:19 AM »
I saw something about -log[H+]. What exactly is -log? I know log is logarithms but I can't find the -log on my calc.

Offline Borek

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Re: Calculate pH values
« Reply #3 on: November 25, 2012, 10:49:48 AM »
- is minus.

Looks like you should start with basic algebra.
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Offline CoCoCo

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Re: Calculate pH values
« Reply #4 on: November 25, 2012, 02:42:46 PM »
I got as my answers:

1. 4

2. 5.4

Offline Borek

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Re: Calculate pH values
« Reply #5 on: November 25, 2012, 03:27:19 PM »
1. 4

Yes.

Quote
2. 5.4

No. How you got this result?
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Offline CoCoCo

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Re: Calculate pH values
« Reply #6 on: November 25, 2012, 08:53:54 PM »
1. 4

Yes.

Quote
2. 5.4

No. How you got this result?

I got 5.4 the same way I got 4. I used:

-log 1x10^-6 M
1 -log 6

How should I have done it?

Offline Borek

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Re: Calculate pH values
« Reply #7 on: November 26, 2012, 04:19:45 AM »
Sorry, but what you wrote makes absolutely no sense, and not seeing what you are doing we are unable to guess.

What is the log10 of 10-6?
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