1 / 31

pH Scale

pH. pH Scale. Logarithmic scale. Measures the concentration of hydrogen ions [H + ] in a solution. Range from 0-14. NEUTRAL, pH=7. (pure water) BASE, pH > 7. (ocean water, milk of magnesia, baking sodea ) ACID, pH < 7. (stomach acid/ HCl , vinegar, soft drinks). pH Scale.

steven-moss
Télécharger la présentation

pH Scale

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

  2. pH Scale • Logarithmic scale. • Measures the concentration of hydrogen ions [H+] in a solution. • Range from 0-14. • NEUTRAL, pH=7. (pure water) • BASE, pH > 7. (ocean water, milk of magnesia, baking sodea) • ACID, pH < 7. (stomach acid/HCl, vinegar, soft drinks)

  3. pH Scale

  4. Log Scale Relationship

  5. Let’s take a look at water • 2H2O H3O+ + OH- • [H3O+][OH-]= 1x10-14M2 • [H3O+]= 1x10-7M • [OH-]= 1x10-7M • Kw= 1x10-14M2

  6. Example 1 • An acid is added to water and gives a hydroxide ion concentration [OH-] of 1.0x10-12M. What is the hydrogen ion concentration [H+] ?

  7. How do we measure the pH of a solution? • Acid-base indicators (ex. litmus paper) • pH meter

  8. Equations • pH = -log[H+] • pOH = -log[OH-] • pH + pOH = 14 • [H+][OH-] = 1x10-14 M2

  9. Example 2: What is the pH of a solution with a hydrogen ion concentration of 1x10-4M ? Is this solution acidic or basic ?

  10. Example 3: What is the hydrogen ion concentration of a solution with a pH of 11 ? Is this solution acidic or basic ?

  11. Example 4: Calculate the [H+] and [OH-] of a vinegar solution with a pH of 2.5.

  12. Now, you try…… • 1) [H3O+] = 1.5x10-6M. Find the pH. • 2) A solution’s pH is 3.72. What are the [H3O+] and [OH-] concentrations in the solution?

  13. Thought Question • When an acid is added to a beaker of water, what happens to the [H3O+] and [OH-] in the solution? Why? What happens to the pH? Why?

  14. Acids and Bases: an Introduction

  15. Acids • Sour Taste • Electrolytes • Identified by the presence of H+ ions (Arrhenius). • Proton (H+) donor (Bronsted-Lowry). • Common Acids: vinegar, citric acid, sulfuric acid, hydrochloric acid.

  16. Bases • Bitter taste • Slippery • Like acids, they are electrolytes • Identified by the presence of OH- ions (Arrhenius). • Proton (H+) acceptor (Bronsted-Lowry).

  17. Strength of Acids and Bases • Based on the concentration of H+ or OH- ions in a solution. • Strong Acids/Bases: completely dissociate into ions in a solution. • Weak Acids/Bases: do NOT completely dissociate into ions in a solution.

  18. HNO3 + NH3 NH4+ + NO3- • Identify the Acid and Base

  19. Stronger the acid, weaker its conjugate base. • Stronger the base, weaker its conjugate acid.

  20. Neutralization ACID + BASE SALT + WATER

  21. Nomenclature

  22. Example 1: HBr • Write name

  23. Now you try, HCl • Write name.

  24. Example 2: Hydrofluoric acid • Write chemical formula

  25. Now you try, hydriodic acid.

  26. Example 3: H2SO4 • Write the name.

  27. Example 4: HClO2 • Write the name.

  28. Try: • HClO3 • HClO • HClO4

  29. Base Nomenclature • Name of cation, name of anion/hydroxide • Ex. NaOH

  30. Tomorrow…. • Briefly brainstorm how we measure the amount of hydrogen ions in a solution? How can we quickly measure the acidity or basicity of a solution?

More Related