2. ACIDS y BASES

3. Characteristics of Acids Taste Sour Affect indicators (red=acid) Neutralize Bases Often produce hydrogen gas pH between 0 and <7

4. Characteristics of Bases Taste Bitter Feel Slippery Neutralize Acids (Antacids) Affect indicators (base=blue) pH between >7 and 14 Dissolve grease (Drano, Windex)

5. Examples of Acids HCl H 2 SO 4 HNO 3 HF Juices

6. Examples of Bases NaOH Ca(OH) 2 KOH Soap, Ammonia, Lye, Baking Soda

7. There are 3 definitions for acids and bases Arrhenius Theory Brønsted-Lowry Theory Lewis Theory

8. pH Scale

12. ON ACIDS… An acid is a substance that ionizes in water to give hydrogen ions (H + ) Arrehenius Theory

13. ON BASES… A base is a substance that ionizes in water to give hydroxide ions (OH - ) Arrehenius Theory

14. An example of the reaction of Hydrochloric Acid: When the HCl breaks apart the free H + is attracted to the H 2 O and forms a HYDRONIUM ION HCl + H 2 O  H 3 O + + Cl -

15. So who is the Arrhenius Acid given: HCl HCl + H 2 O  H 3 O + + Cl - Why? Because it produces H +

16. An example of the reaction of Potassium Hydroxide: When the KOH breaks apart it forms the HYDROXIDE ION (OH - ) KOH + H 2 O  K + + 2OH -

17. So who is the Arrhenius Base given: KOH KOH + H 2 O  K + + 2OH - Why? Because it produces OH -

18. The world was cool with the Arrehenius definition until NH 3 (Ammonia) came along. When combined with water it increased the number of OH - ions…looks like we need a new definition

19. ON ACIDS… Acids are substances that are capable of donating a proton Brønsted-Lowry Theory

20. ON BASES… Bases are substances capable of accepting a proton Brønsted-Lowry Theory

21. Example Brønsted Acids and Bases: Here, H 2 O acts as a Brønsted acid by donating a proton to NH 3 which acts as a Brønsted base. NH 3 + H 2 O  NH 4 + + OH -

22. Example Brønsted Acids and Bases: In this case, NH 4 + acts as an acid which donates a proton to OH -. OH - acts as a base. NH 4 + + OH -  NH 3 + H 2 O

23. ON ACIDS… Acids are substances that are electron-pair receptors Lewis Theory

24. ON BASES… Bases are substances capable of donating electron-pairs Lewis Theory

25. The substance that remains after an acid has donated a H + ion Conjugate Base

26. The substance formed when a base accepts a H + ion Conjugate Acid

27. Conjugate Acids and Base For example, NH 4 + is the conjugate acid of NH 3 (1 st equation), and NH 3 is the conjugate base of NH 4 + (2 nd equation). NH 3 + H 2 O  NH 4 + + OH - NH 4 + + OH -  NH 3 + H 2 O

28. Interesting fact… Water can act as an acid or a base!!!

29. A substance that can act as either an acid or a base. Amphoteric

30. For any reaction: HA + H 2 O  H 3 O + + A - If HA is a strong acid because it gives up its proton readily, then A - is a weak base because it has little affinity for the proton.

31. For any reaction: HA + H 2 O  H 3 O + + A - If HA is a weak acid because it donates very few protons to the water, then A - has a high affinity for a proton, and A - is a stronger base than water.