1 / 19

Acid – Base Theory

Acid – Base Theory. Definitions:. Arrhenius: An acid is a substance that increases the H + (or H 3 O + ) concentration in an aqueous solution. HCl + H 2 O  H 3 O + + Cl -. HCl  H + + Cl -. A base is a substance that increases the OH - concentration

salvador-stanton
Télécharger la présentation

Acid – Base Theory

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. Acid – Base Theory

  2. Definitions: Arrhenius: An acid is a substance that increases the H+ (or H3O+) concentration in an aqueous solution. HCl + H 2O  H3O+ + Cl- HCl  H+ + Cl- A base is a substance that increases the OH- concentration in an aqueous solution. NaOH(s)  Na+ + OH- What about Na2CO3 ????

  3. Bronsted-Lowry: HCl(aq) + NaOH(aq) → HOH + NaCl Acid = a proton donor in a RXN Base = a proton acceptor in a RXN

  4. Lewis: An acid is an electron pair acceptor H+ acid .. H:O:H .. A base is an electron pair donor water .. :O:H- ..

  5. Acid/Base reactions: Produce water and a salt (and sometimes carbon dioxide). Hint: concentrate on the water first. Remember, water has the formula HOH. Complete and balance the following: HCl + KOH  HOH + KCl HCl + Ca(OH)2 2 2HOH + CaCl2 Require equal numbers

  6. 1. Ba(OH)2 + H3PO4 2. HC2H3O2 + NaOH 3. H2SO4 + KOH 4. H2CO3 + NaOH 5. Na2CO3 + HCl 

  7. 6. NH4OH + H2SO4 7. NH3 + HCl  Give a definition of an acid: An acid is a proton donor (H+) Give a definition of a base: A base is a proton acceptor

  8. Conjugate acids and Conjugate bases HCl + KOH  HOH + KCl acid base conj. base conj. acid Na2CO3 + 2HCl  H2CO3 + 2NaCl acid conj. base base conj. acid Na2CO3 + 2HCl  H2O + CO2(g) + 2NaCl acid conj. acid base conj. base

  9. NH3 + HCl  NH4+ + Cl-

  10. What is a strong Acid? An Acid that is 100% ionized in water. Strong Acids: 100% ionized (completely dissociated) in water. HCl + H2O  H3O+ + Cl- often written as: HCl  H+ + Cl-

  11. Strong Acids: 100% ionized (completely dissociated) in water. HCl + H2O  H3O+ + Cl- Strong Acids: Perchloric HClO4 Chloric, HClO3 Hydrobromic, HBr Hydrochloric, HCl Hydroiodic, HI Nitric, HNO3 Sulfuric, H2SO4

  12. What is a strong Base? A base that is completely dissociated in water (highly soluble). NaOH(s)  Na+ + OH- Strong Bases: Group 1A metal hydroxides (LiOH, NaOH, KOH, RbOH, CsOH) Heavy Group 2A metal hydroxides [Ca(OH)2, Sr(OH)2, and Ba(OH)2]

  13. Weak Acids: “The Rest”

  14. Strong Acids: 100% ionized (completely dissociated) in water. HCl + H2O  H3O+ + Cl- Note the “one way arrow”. Weak Acids: Only a small % (dissociated) in water. HC2H3O2 + H2O H3O+ + C2H3O2- Note the “2-way” arrow. Why are they different?

  15. Strong Acids: HCl HCl HCl HCl HCl (H2O) ADD WATER to MOLECULAR ACID

  16. Strong Acids: Cl- H3O+ (H2O) Cl- H3O+ H3O+ Cl- Cl- H3O+ H3O+ Cl- Note: No HCl molecules remain in solution, all have been ionized in water.

  17. Weak Acid Ionization: HC2H3O2 HC2H3O2 (H2O) HC2H3O2 HC2H3O2  HC2H3O2 Add water to MOLECULES of WEAK Acid

  18. Weak Acid Ionization: HC2H3O2 HC2H3O2 H30+ C2H3O2- HC2H3O2 (H2O) HC2H3O2  H30+ C2H3O2- HC2H3O2 HC2H3O2 Note: At any given time only a small portion of the acid molecules are ionized and since reactions are running in BOTH directions the mixture composition stays the same. This gives rise to an Equilbrium expression, Ka

More Related