This document provides an introduction to acids, bases and salts. It discusses key concepts including: 1) Acids have a sour taste and feel, bases have a bitter taste and slippery feel. Acids react vigorously with metals while bases don't. 2) When acids and bases are mixed, a neutralization reaction occurs producing water and a salt. 3) Arrhenius defined acids as substances that release H+ ions in water and bases as those that release OH- ions. Bronsted-Lowry expanded this to include acids as proton donors and bases as proton acceptors. 4) The pH scale is used to measure acidity/basicity, with acids having a pH <7 and bases

1. Acids Bases and Salts A video lesson

2. Introduction Ascorbic acid is better known as .. When dissolved in water, what taste do acids have? What kind of taste do bases have? Vitamin C Sour, tart Bitter

3. Introduction What kind of feel do acids have? What kind of feel do bases have? Acids and bases are both electrolytes. What does this mean? Like water, sting Slippery Good conductors of electric current

4. Introduction How do acids react with metals? How do bases react with metals? What is a good way of testing if a liquid is an acid or base? Vigorously They don’t pH indicator (litmus) paper

5. Arrhenius Acids and Bases What is the process that occurs when acids and bases are mixed? What is produced when an acid and base are mixed? What happens to the HCl molecule in water? Neutralization Water and a salt (ionic compound) It dissociates into ions

6. Arrhenius Acids and Bases The positively charged H + ion is called a CATION and the negatively charged Cl - ion is called an ANION . The hydrogen ion is just a PROTON

7. Arrhenius Acids and Bases When a base is dissolved in water, it releases an OH - ion. Arrhenius defined acids as substances that release H + ions when dissolved in water… …and bases are substances that generate OH - ions when dissolved in water.

8. Arrhenius Acids and Bases What is produced when the H+ from an acid is mixed with an OH- from a base? H 2 O (WATER) Acid + Base  WATER + SALT

9. Bronstead-Lowry Acids and Bases Arrhenius’ definition could not explain why BAKING SODA is a base. According to Bronstead-Lowry An acid is anything that DONATES a proton A base is anything that ACCEPTS a proton. Both acids and bases are related to the concentration of H + .

10. Bronstead-Lowry Acids and Bases Acids INCREASE H + concentration, while bases DECREASE H + concentration. The acidity or basicity of something can be measured by its PROTON concentration.

11. Strong and weak acids and bases A strong acid READILY TRANSFERS H+ ions to water. The more COMPLETE the transfer of H+ ions, the STRONGER the acid.

12. Strong and weak acids and bases Why is vinegar a weak acid? It does not readily transfer its ions to water

13. Conjugate Acid-Base Pairs Conjugate acid-base pairs differ by only ONE PROTON . There is an INVERSE relationship between the strength of an acid or base and its conjugate base or acid. The STRONGER the acid, the WEAKER its conjugate base. The STRONGER the base, the WEAKER its conjugate acid.

14. The pH scale In pure water, the amount of H 3 O + ions is 10 -7 moles/liter. What is the name of the scale that is used to measure acidity or basicity? The pH scale Where are acids on the scale? <7 Where are bases on the scale? >7

15. The pH in the chemistry of nature Rainfall with a pH below 5.6 is called acid rain . Human blood must have a pH between 7.35 and 7.45 . Buffers resist changes in pH level.