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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: CoCoCo on November 24, 2012, 06:59:07 PM

Title: Calculate pH values
Post by: CoCoCo 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.
Title: Re: Calculate pH values
Post by: Borek 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.
Title: Re: Calculate pH values
Post by: CoCoCo 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.
Title: Re: Calculate pH values
Post by: Borek on November 25, 2012, 10:49:48 AM: - is minus.

Looks like you should start with basic algebra.
Title: Re: Calculate pH values
Post by: CoCoCo on November 25, 2012, 02:42:46 PM: I got as my answers:

1. 4

2. 5.4
Title: Re: Calculate pH values
Post by: Borek on November 25, 2012, 03:27:19 PM: Quote from: CoCoCo on November 25, 2012, 02:42:46 PM
1. 4

Yes.

Quote
2. 5.4

No. How you got this result?
Title: Re: Calculate pH values
Post by: CoCoCo on November 25, 2012, 08:53:54 PM: Quote from: Borek on November 25, 2012, 03:27:19 PM
Quote from: CoCoCo on November 25, 2012, 02:42:46 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?
Title: Re: Calculate pH values
Post by: Borek 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?