1 / 13

pH and pOH

pH and pOH. Measuring acidity and basicity. pH. The pH scale is used to measure the acidity of a solution. pH is a measure of the concentration of hydronium ions, [H 3 O + ], in a solution. The scale ranges from 0 - 14 A pH value of 7 indicates neutrality.

penda
Download Presentation

pH and pOH

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. pH and pOH Measuring acidity and basicity.

  2. pH • The pH scale is used to measure the acidity of a solution. • pH is a measure of the concentration of hydronium ions, [H3O+], in a solution. • The scale ranges from 0 - 14 • A pH value of 7indicates neutrality. • A pH value of 0indicates the strongest acid. • A pH value of 14 indicates the weakest acid.

  3. pH

  4. Calculations Involving pH pH = -log [H3O+] • Concentration of hydronium ions is usually expressed in scientific notation form. • Coefficient must be greater than or equal to 1 and less than 10. • Exponent is a number between -14 and 0.

  5. Interpreting pH Values • When coefficient equals one, the pH is equal to the exponent (without negative sign). • Once the pH is determined: • pH less than 7 means acidic • pH of exactly 7 means neutral • pH more than 7 means basic

  6. pH Problems • What is the pH of a solution if the concentration of hydronium ions is 1 x 10-3? • Use exponent to determine pH: • pH = 3 • Is this solution acidic, neutral, or basic? • pH is less than 7: • Solution is acidic.

  7. pH Problems • If the pH of a solution is 10, what is the concentration of hydronium ions? • Convert the pH to the exponent in scientific notation form: • Concentration of hydronium ions = 1 x 10-10 • Is this solution acidic, neutral, or basic? • pH is more than 7: • Solution is basic.

  8. pOH • The pOHscale is used to measure the basicity of a solution. • pOHis a measure of the concentration of hydroxide ions, [OH-], in a solution. • The scale ranges from 0 - 14 • A pOHvalue of 7indicates neutrality. • A pOHvalue of 0indicates the strongest base. • A pOHvalue of 14 indicates the weakest base.

  9. Calculations Involving pOH pOH= -log [OH-] • When coefficient equals one, the pOHis equal to the exponent (without negative sign). • Once the pOHis determined: • pOHless than 7 means basic • pOH of exactly 7 means neutral • pOH more than 7 means acidic

  10. pOH Problems • What is the pOHof a solution if the concentration of hydroxide ions is 1 x 10-8? • Use exponent to determine pOH: • pOH = 8 • Is this solution acidic, neutral, or basic? • pOH is more than 7: • Solution is acidic.

  11. pOH Problems • If the pOHof a solution is 7, what is the concentration of hydroxide ions? • Convert the pOH to the exponent in scientific notation form: • Concentration of hydroxide ions = 1 x 10-7 • Is this solution acidic, neutral, or basic? • pOH is exactly 7: • Solution is neutral.

  12. pH and pOH of Pure Water [H3O+]= (1 x 10-7) & [OH-] = (1 x 10-7) • What is the pH of pure water? • 7 • What is the pOH of pure water? • 7 • What is the sum of the pH and pOH of pure water? • 14

  13. Relationship Between pH & pOH • pH + pOH = 14 • pH = 14 - pOH • pOH = 14 - pH Most Basic Most Acidic

More Related