1 / 25

Acids and Bases Chapters 15

Acids and Bases Chapters 15. I. Introduction A. Characteristics of acids 1) formulas BEGIN with Hydrogen 2) taste sour 3) turn blue litmus paper to RED 4) react with and neutralize bases B. Characteristics of Bases 1) formulas typically END with OH

isi
Download Presentation

Acids and Bases Chapters 15

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. Acids and Bases Chapters 15

  2. I. Introduction A. Characteristics of acids 1) formulas BEGIN with Hydrogen 2) taste sour 3) turn blue litmus paper to RED 4) react with and neutralize bases B. Characteristics of Bases 1) formulas typically END with OH 2) taste bitter 3) feel slippery 4) turn red litmus paper BLUE 5) react with and neutralize acids

  3. I. Review of Acid Nomenclature A. Binary acids hydro + (root) +ic acid ex: HCl - hydrochloric acid HI - hydroiodic acid B. Polyatomic acids (a.k.a oxyacids) 1) polyatomic ions ending with -ATE (root) + ic acid ex: H2SO4 - sulfuric acid HClO3 - chloric acid 2) polyatomic ions ending with -ITE (root) + ous acid ex:HNO2 - nitrous acid

  4. Practice Nomenclature a) HClO2 b) H2S c) HIO4 d) HBrO e) HMnO4 f) H2CrO4 g) HOH

  5. II. Conjugate Acid and Base Theory A. Behaving like an Acid means to GIVE AWAY a H-atom B. Behaving like a Base means to ACCEPT an H-atom C. Ionization reactions always involve acid/base pairs: ex: HCN + H2O <-----> CN - + H3O + base conj. base conj. acid acid ex: NH3 + H2O <------> NH4+ + OH - conj. acid conj. base base acid amphoteric - able to act as either acid or base

  6. Do Now 1) Indicate the conjugate base of H2S 2) Indicate the conjugate acid of HSO4- 3) Indicate the conjugate base of HPO4-2 4) Indicate the conjugate acid of HCO3-

  7. notes: 1) acids lose H to become a conjugate base 2) bases accept H to become a conjugate acid 3) WEAK “originals” make STRONG conjugates 4) STRONG “originals” make WEAK conjugates ex: HCN + H2O <-----> CN - + H3O + weak weak strong strong ex: NH3 + H2O <------> NH4+ + OH - weak weak strong strong notes: 1) H3O + is always a STRONG ACID 2) OH - is always a STRONG BASE

  8. Strengths of Acids • Binary acids • A. Within a group … • 1) the weaker the bond the stronger the acid • 2) weaker bonds occur with larger anions B. Within a period 1) the more electronegative anion the stronger the acid ex: Arrange this from weaker (1) to stronger HI HF HCl HBr

  9. Strengths of Acids II. Oxyacids A. With the same # of oxygens… - more electronegative center = stronger HClO HBrO HIO B. Same atoms, more oxygens - the more oxygen there are = stronger the acid HClO HClO2 HClO3 HClO4

  10. III. Strengths of Acids and Bases A. Strong acids HCl HBr HI Weak acids all the others HNO3 HClO3 HClO4 H2SO4 Weak bases NH3 covalent compounds with C, H, N in the formulas B . Strong bases (Group IA) - OH (Group IIA) - OH CH3NH2 Ca(OH)2 HNO2 Na2CO3 ex: HF

  11. IV. Acid - Base Theories A. Three prevailing theories exist to define acids/bases 1) Arrhenius - acids = H in formula - bases = OH in formula ex: HCl LiOH 2) Bronsted - Lowry - acids = proton donor - bases = proton acceptor ex: HCl NH3 3) Lewis - acids = electron pair acceptor - bases = electron pair donor ex: BF3 NH3

  12. DO NOW H2O + HC2H3O2 => H3O+ + C2H3O2- Identify the acid/bases and conjugate acid bases and then identify as weak or strong.

  13. ex: HCN + H2O <-----> CN - + H3O + ex: NH3 + H2O <------> NH4+ + OH - Bronsted acids: Bronsted bases

  14. V. The pH Scale A. Concentrations of H+ and OH- are often converted to a more convenient mathematical form: 1) pH = - log [H+] ex: instead of [H+] = 1.00 x10 -6 M . . . . . . . . pH = 6.000 How? pH = - log (1.0 x 10 -6) = 6.00 2) pOH = - log [OH-] ex: instead of [OH-] = 2.0 x10 -3 M . . . . . . . . pOH = 2.70 How? pOH = -log (2.0 x10 -3 ) = 2.70

  15. B. The ionization of water causes the product of [H+] and [OH-] to always equal a constant: 1) [H+] [OH-] = 1.0 x 10 -14 (known as Kw) 2) If the concentration of one is known, the other can be calculated Ex: [H+] = 1.00 x 10-4 M . . . . . . [OH-1] = 1.00 x 10-10 M OR . . . . . . If pH = 4, then pOH = ????? pOH = 10

  16. Practice: • What is the pH of 2.50 x 10-3 M HCl? • 2) What is the pOH of 3.5 x 10-8 M HNO3? • 3) What is the [H+] of a solution with pH = 9.20? • 4) What is the [OH-] of a solution with pH = 6.85?

  17. C. Acidic/Basic solutions are determined by their pH values: 1) pH < 7 . . . . . . . acidic 2) pH > 7 . . . . . . . basic 3) pH = 7 . . . . . . . neutral

  18. pH Chart Showing Common Substances

  19. Try It NowWrite the reaction that occurs when NaOH is added to HCl.

  20. VI. Acid-Base Titrations • An acid and a base react to form: • NaOH + HCl NaCl + H2O • base + acid  salt + water • B. Neutralization • 1) occurs when an acid and a base react • 2) same as double replacement reaction

  21. C. A solution is neutral when moles acid = moles base Ex: Suppose 42.00 mL of a 0.150 M NaOH solution is required to neutralize 50.00 mL of an unknown HCl solution. What is the molarity of the HCl solution? Answer: 0.126 M HCl

  22. Ex: Suppose 42.00 mL of a 0.150 M NaOH solution is required to neutralize 50.00 mL of an unknown H2SO4 solution. What is the molarity of the H2SO4 solution? Answer: 0.0630 M H2SO4

  23. Ex: If 50.00 mL of a 0.2000 M HCl solution is titrated with 0.1500 M NaOH…. • What is the pH before any NaOH has been added? • What is the pH after 10.00 mL of base has been added? • What is the pH after 70.00 mL of base have been added?

  24. Review • List 3 characteristics of acids and bases • What is the conjugate base of OH- ? • What is the [OH-] of 2.5 x 10-8 M HCl? • Write the formula for hydroiodic acid. • Identify NH3 as Arrhenius acid/base, Bronsted acid/base, or Lewis acid/base

  25. Review 6) What is the pH of 3.0 x 10-4 M NaOH? 7) What is the pH after 5.0 mL of 0.20 M HCl is titrated with 8.0 mL of 0.10M NaOH? 8) How many mL’s of 0.250 M NaOH are required to neutralize 30 mL of 0.15M HCl? 9) Which acid is strongest … HIO or HIO3 10) Which base is strongest … Cl- or F- ?

More Related