1/7/2014regular chemistry assignment #74 intro to acids & bases
TRANSCRIPT
04/10/23 Regular Chemistry
Assignment #74Intro to Acids & Bases
04/10/23 Regular Chemistry
Properties
Acids
• Taste Sour• Aqueous• Electrolytic
• Ions in Solution• H+ Ions
• Corrosive• Feel Watery• Low pH
Bases
• Taste Bitter• Aqueous• Electrolytic
• Ions in Solution• OH- Ions
• Corrosive• Feel Slippery• High pH
04/10/23 Regular Chemistry
Properties
Acids
• Taste Sour• Aqueous• Electrolytic
• Ions in Solution• H+ Ions
• Corrosive• Feel Watery• Low pH (pH<7)
Bases
• Taste Bitter• Aqueous• Electrolytic
• Ions in Solution• OH- Ions
• Corrosive• Feel Slippery• High pH (pH>7)
04/10/23 Regular Chemistry
Arrhenius Definition• Svante Arrhenius• Acids Contain Hydrogen Ion (H+)• Bases Contain Hydroxide Ion
(OH-)• HCl, KOH• Minor Problem:
• H+ Ion Is Unstable
• H+(aq.) H3O+
(aq.)
• Hydronium Ion• Bigger Problem:
• NH3
• It’s a Base
04/10/23 Regular Chemistry
Arrhenius Acid/Base Reaction
• Combine sulfuric acid with aqueous potassium hydroxide.
• H2SO4(aq.) + KOH(aq.)
• Double Replacement
04/10/23 Regular Chemistry
Arrhenius Acid/Base Reaction
• Combine sulfuric acid with aqueous potassium hydroxide.
• H2SO4(aq.) + KOH(aq.) H2O + K2SO4
04/10/23 Regular Chemistry
Arrhenius Acid/Base Reaction
• Combine sulfuric acid with aqueous potassium hydroxide.
• H2SO4(aq.) + 2 KOH(aq.) 2 H2O + K2SO4
04/10/23 Regular Chemistry
Arrhenius Acid/Base Reaction
• Combine sulfuric acid with aqueous potassium hydroxide.
• H2SO4(aq.) + 2 KOH(aq.) 2 H2O(l.) + K2SO4(aq.)
• Spectator Ions:
• K+ and SO42-
• Net-Ionic Equation
• 2 H+(aq.) + 2 OH-
(aq.) 2 H2O(l.)
• 2 H3O+(aq.) + 2 OH-
(aq.) 4 H2O(l.)
04/10/23 Regular Chemistry
Arrhenius Acid/Base Reaction
• Combine sulfuric acid with aqueous potassium hydroxide.
• H2SO4(aq.) + 2 KOH(aq.) 2 H2O(l.) + K2SO4(aq.)
• Arrhenius acid/base reactions always make water and a salt.
• Potassium sulfate is the salt in this reaction.
04/10/23 Regular Chemistry
Brønsted-Lowry Definition
• Johannes Brønsted and Thomas Lowry
• Acids Donate a Proton• H+ Ion is a Proton
• HCl, HNO3
• Bases Accept a Proton• OH-
• NH3
04/10/23 Regular Chemistry
Brønsted-Lowry Acid/Base Reaction
• Combine hydrochloric acid with aqueous ammonia.
• HCl(aq.) + NH3(aq.)
• HCl is the acid (Donates H+)
• NH3 is the base (Accepts H+)
04/10/23 Regular Chemistry
Brønsted-Lowry Acid/Base Reaction
• Combine hydrochloric acid with aqueous ammonia.
• HCl(aq.) + NH3(aq.) Cl-(aq.) + NH4+
(aq.)
• HCl is the acid (Donates H+)
• NH3 is the base (Accepts H+)
• Brønsted-Lowry acid/base reactions just make a salt, no water.
• Ammonium chloride is the salt in this reaction.
04/10/23 Regular Chemistry
Conjugate Acids and Bases
• The acids and bases in the reverse reaction are called conjugates.
• HCl(aq.) + NH3(aq.) Cl-(aq.) + NH4+
(aq.)
• Conjugate Acid:• Conjugate Base:
04/10/23 Regular Chemistry
Conjugate Acids and Bases
• The acids and bases in the reverse reaction are called conjugates.
• HCl(aq.) + NH3(aq.) Cl-(aq.) + NH4+
(aq.)
• Conjugate Acid: NH4+
• Conjugate Base: Cl-
• The acid becomes the conjugate base, and the base becomes the conjugate acid.
04/10/23 Regular Chemistry
More Brønsted-Lowry Acid/Base Reactions
• HCl(aq.) + H2O(l.)
• Hydrochloric acid is the acid, so water must be the base.
04/10/23 Regular Chemistry
More Brønsted-Lowry Acid/Base Reactions
• HCl(aq.) + H2O(l.) Cl-(aq.) + H3O+(aq.)
• Conjugate Acid and Conjugate Base?• Conjugate Acid is Hydronium Ion• Conjugate Base is Chloride Ion
04/10/23 Regular Chemistry
More Brønsted-Lowry Acid/Base Reactions
• NH3(aq.) + H2O(l.)
• Ammonia the base, so water must be the acid.
04/10/23 Regular Chemistry
More Brønsted-Lowry Acid/Base Reactions
• NH3(aq.) + H2O(l.) NH4+
(aq.) + OH-(aq.)
• Conjugate Acid and Conjugate Base?• Conjugate Acid is Ammonium Ion• Conjugate Base is Hydroxide Ion
04/10/23 Regular Chemistry
Amphoteric
• HCl(aq.) + H2O(l.) Cl-(aq.) + H3O+(aq.)
• Water is the base.
• NH3(aq.) + H2O(l.) NH4+
(aq.) + OH-(aq.)
• Water is the acid.
• Water can act as an acid or a base.• Water is amphoteric.• Amphoteric Does Not Mean Neutral.
04/10/23 Regular Chemistry
Polyprotic Acids
• Can donate more than one proton.
• H2SO4 is Diprotic.
• First Proton:
• H2SO4(aq.) + H2O(l.) HSO4-(aq.) + H3O+
(aq.)
• Second Proton:
• HSO4-(aq.) + H2O(l.) SO4
2-(aq.) + H3O+
(aq.)
• Other polyprotic acids:
• H2CO3
• H3PO4
04/10/23 Regular Chemistry
Summary• Properties of Acids and Bases
• Taste (Sour vs. Bitter)• Touch (Slippery Bases)• Conductivity (Both Electrolytic)• pH
• Arrhenius Definition• Acids Have H+ / Bases Have OH-
• Brønsted-Lowry Definition• Acids Donate a Proton• Bases Accept a Proton
• Hydronium Ion• Conjugate Acids and Bases
• Water Can Be Amphoteric• Polyprotic Acids
04/10/23 Regular Chemistry
Tonight's Assignment
Assignment Reading Problems
Number Sections Pages Questions Pages
74 18-1 594 -- 604 1,2,3,20 / 4 622 -- 623 / 919