1 / 15

Understanding the Strengths of Acids and Bases: Strong vs. Weak

This chapter covers the fundamental differences between strong and weak acids and bases, emphasizing their dissociation in water. Strong acids and bases completely ionize, acting as strong electrolytes; examples include HCl and NaOH. In contrast, weak acids and bases, such as acetic acid and ammonia, partially dissociate. The chapter also explains the significance of pH as a measure of hydrogen ion concentration, illustrating how it relates to acidity and basicity. Additional focus is placed on blood pH and the role of buffers in maintaining it.

senta
Télécharger la présentation

Understanding the Strengths of Acids and Bases: Strong vs. Weak

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. Chapter 25 Lesson 2 Strengths of Acids and Bases

  2. - - + + Strong and Weak Acids and Bases • The strength of an acid or base depends on how many acid or base particles dissociate into ions in water. • Strong Acid/Base • 100% ions in water • strong electrolyte • HCl, HNO3, NaOH, LiOH • Weak Acid/Base • few ions in water • weak electrolyte • HC2H3O2, NH3

  3. Strong and Weak Acids • Equations describing dissociation can be written in two ways. • In strong acids, such as HCl, nearly all the acid dissociates. • This is shown by writing the equation using a single arrow pointing toward the ions that are formed.

  4. Strong and Weak Acids • Equations describing the dissociation of weak acids, such as acetic acid, are written using double arrows pointing in opposite directions. • This means that only some of the CH3COOH dissociates and the reaction does not go to completion.

  5. Strong and Weak Bases • A strong base dissociates completely in solution • The following equation shows the dissociation of sodium hydroxide, a strong base.

  6. Strong and Weak Bases • This dissociation of ammonia, which is a weak base, is shown using double arrows to indicate that not all the ammonia ionizes. It only produces a few ions in water.

  7. pH of a Solution • The pH of a solution is a measure of the concentration of H+ ions in it. • The greater the H+ concentration is, the lower the pH is and the more acidic the solution is. • The pH measures how acidic or basic a solution is.

  8. pH Scale • pH • a measure of the concentration of H3O+ ions in solution • measured with a pH meter or an indicator with a wide color range 14 0 7 NEUTRAL • INCREASING • BASICITY INCREASING ACIDITY

  9. pH Scale pH of Common Substances

  10. Strength and Concentration • In contrast, the terms dilute and concentrated are used to indicate the concentration of a solution, which is the amount of acid or base dissolved in the solution.

  11. Strength and Concentration • It is possible to have dilute solutions of strong acids and bases and concentrated solutions of weak acids and bases

  12. Blood pH • In order to carry out its many functions properly, the pH of blood must remain between 7.0 and 7.8. • The main reason for this is that enzymes, the protein molecules that act as catalysts for many reactions in the body, cannot work outside this pH range.

  13. Blood pH • Your blood contains compounds called buffers that enable small amounts of acids or bases to be absorbed without harmful effects. • Buffers are solutions containing ions that react with additional acids or bases to minimize their effects on pH.

  14. ConcepTest • Which of the following "molecular" pictures best represents a concentrated solution of the weak acid HA? A B

  15. ConcepTest • Is the following statement TRUE or FALSE? • A strong acid has a lower pH than a weak acid. • TRUE - Strong/weak refers to amount of ionization whereas pH refers to concentration of H+.

More Related