1 / 14

Pure Water is Neutral

Explore the concept of pH in pure water and chemical solutions, including the relationship between hydronium and hydroxide ions, the ion product constant Kw, and calculations to determine pH and pOH levels.

tayloredward
Download Presentation

Pure Water is Neutral

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Pure Water is Neutral Pure water contains small, but equal amounts of ions: H3O+ and OH- H2O + H2O H3O+ + OH- hydronium hydroxide ion ion 1 x 10-7 M1 x 10-7 M H3O+ OH-

  2. [H3O+ ] = [OH-] = 1 x 10-7 M • Since they are equal, a neutral solution results from water • Kw = [H3O+ ] x [OH-] = 1 x 10-14M2 • Kw is called the “ion product constant” • The equation is applicable to pure water and aqueous solutions

  3. pH and pOH • pH = -log [H3O+] • pOH = -log [OH-] • pH + pOH = 14 • [H3O+] = antilog -pH

  4. 100 10-1 10-3 10-5 10-7 10-9 10-11 10-13 10-14 14 13 11 9 7 5 3 1 0 10-14 10-13 10-11 10-9 10-7 10-5 10-3 10-1 100 [H+] pH 0 1 3 5 7 9 11 13 14 Acidic Neutral Basic pOH [OH-]

  5. Using Kw The [OH- ] of a solution is 1.0 x 10- 3M. What is the [H3O+]? Kw = [H3O+ ] [OH- ] = 1.0 x 10-14 M2 [H3O+] = 1.0 x 10-14 M2 [OH-] [H3O+] = 1.0 x 10-14 M2= 1.0 x 10-11 M 1.0 x 10- 3 M

  6. Using the Calculator 1.0 x 10 -14 1.0 x 10-3 Enter1.0 EE +/- 14 1.0 EE+/- 3 = 1.0 x 10 -11

  7. Find the hydroxide ion concentration of 3.0  10-2 M HCl. [H3O+][OH-] = 1.0  10-14 [3.0  10-2][OH-] = 1.0  10-14 [OH-] = 3.3  10-13 M Acidic or basic? Acidic

  8. pH In the expression for [H3O+] 1 x 10-exponent the exponent = pH [H3O+] = 1 x 10-pH M

  9. Some [H3O+] and pH [H3O+] pH 1 x 10-5 M 5 1 x 10-9 M 9 1 x 10-11M 11

  10. Learning Check The pH of a soap is 10. What is the [H3O+] of the soap solution? [H3O+] = 1 x 10-pH M = 1 x 10-10 M

  11. pH on the Calculator [H3O+] is 4.5 x 10-6 M pH = ? pH = -log [H3O+] pH = 4.5 EXP(or EE) 6 +/- LOG +/- = 5.3

  12. pH Scale • What is the pH of 0.050 M HNO3? pH = -log[H3O+] pH = -log[0.050] pH = 1.3 Acidic or basic? Acidic

  13. pH Scale • What is the molarity of HBr in a solution that has a pOH of 9.6? • [H3O+] = antilog -pH pH + pOH = 14 pH + 9.6 = 14 pH = 4.4 pH = -log[H3O+] 4.4 = -log[H3O+] -4.4 = log[H3O+] [H3O+] = 4.0  10-5 M HBr Acidic

  14. Learning Check Identify each solution as 1. acidic 2. basic 3. neutral A. _1__ HCl with a pH = 1.5 B. _2__ Pancreatic fluid [H+] = 1 x 10-8 M C. _1__ Sprite soft drink pH = 3.0 D. _3__ pH = 7.0 E. _1__ [OH-] = 3 x 10-10 M F. _2__ [H+] = 5 x 10-12 M

More Related