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posted by  Exia on 10/19/2008 12:38:43 AM  |  status: Live  

How do I do this?

Course Textbook Chapter Problem
General Chemistry Chemistry: A Molecular Approach 15 15.55
Question Details:
I'm really having trouble figuring this out.

I have .13 M of HCl and I'm asked to determine the [H3O+] and [OH-]. Can someone show me how to find the answer?

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posted by Rubisco on 10/19/2008 1:09:37 AM  |  status: Live
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Exia's comment:
"Very well explained. Thank you for your help"
Response Details:

Ok HCl is a strong acid that disassociates 100% (well almost but good enough for general chemistry problems)
For these reactions use the ICE table (some people call it a RICE table)
R-reaction
I - Initial
C - Change
E - Equilibrium

Equation follows:
HCl     --->  H+ + Cl-

Table
R
  HCL  H+  Cl-
I
  .13M  0  0
C
  -.13M  +.13M  +.13M
E
  0  .13M  .13M

So at the end of the reaction we get .13M [H+] which is the same thing as [H3O+] (very concentrated, acidic)

To get OH concentration we perform the following calculation

[OH-][H3O+] = 1 x 10-14

Now plug-in and solve

[OH](0.13M) = 1 x 10-14

[OH] = 7.69 x 10-14 M  <-- very small, dilute concentration
Please rate my answers. Thanks. If you have questions send me a PM
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