1. P.Sci. Unit 11 Cont. Solutions, Acids, and Bases Chapter 8

2. Acids and Bases

3. Acids Contain at least one hydrogen atom that can be removed when the acid is dissolved in water. These form hydronium ions, H 3 O +.

4. Properties of Acids H+ ions interact with water molecules to form H 3 O + ions. Taste sour. Have a pH less than 7. Are electrolytes because in solution they contain ions.

5. Properties cont. Are corrosive and can cause severe burns. Reacts with indicators to produce a change in color (litmus turns red). Neutralize bases to form a salt and water.

6. Bases Forms hydroxide ions (OH-) in a water solution.

7. Properties of Bases Many are crystalline solids. Feel slippery. Have a bitter taste. Have a pH of greater than 7. Are electrolytes because in solution they contain ions.

8. Properties cont. Are corrosive and can cause severe burns. Reacts with indicators to produce a change in color (litmus turns blue). Neutralize acids to form a salt and water.

9. Strength of Acids and Bases The strength of an acid or base depends on how completely a compound separates into ions when dissolved in water. Ions can carry an electric charge so a strong acid will carry more electricity than weak acid.

10. Strength of Acids Acids that ionize almost completely in a solution is a strong acid. Ex: HCl, HNO 3, and H 2 SO 4

11. Strength of Bases Bases that dissociate completely in a solution is a strong base Ex: NaOH

12. Strength vs. Concentration Strong and weak – tells how easy the acid or base dissociates in solution. Concentration – The amount of acid or base in a solution – It is possible to have a dilute concentration of a strong acid that would be less harmful than a concentrated weak acid.

13. pH pH means potential of hydrogen It is a measure of the concentration of H+ ions. The greater the concentration of H+ the lower the pH. The lower the pH – the stronger the acid. The pH range goes from 0 – 14

14. To determine the pH of a solution an indicator is used (an organic compound that changes color in the presence of an acid or base.) Strong Acid Neutral Strong Base 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH scale

15. Salt Neutralization is a chemical reaction between an acid and a base that takes place in a water solution. Salts are formed when the negative ion from an acid combine with the positive ions from a base. Acid + base → salt + water Salt (NaCl) is essential for most animals