Reactions in Aqueous Solutions I

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Reactions in Aqueous Solutions I
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Properties of Aqueous Solutions of Acids Bases

• Acidic properties
• taste sour
• change the colors of indicators
• turn litmus red
• react with metals to generate H2(g)
• react with carbonates and bicarbonates to form
  salts, carbon dioxide and water
• aqueous solutions conduct electricity
• react with bases to produce salt and water

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Properties of Aqueous Solutions of Acids Bases

• Basic properties
• taste bitter
• feel slippery
• change colors of indicators
• turn litmus blue
• react with acids to form salts and water
• aqueous solutions conduct electricity

SOAP
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Arrhenius Acid

• Acid - A substance that produces hydrogen ions,
  H, in aqueous solutions.

HCl ? H Cl- HCN ? H CN-
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Arrhenius Base

• Base - A substance that produces hydroxide, OH-,
  in aqueous solutions.

KOH ? K OH- NH3 H2O ? NH4 OH-
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Arrhenius Theory

• neutralization - combination of H (or H3O) with
  OH-
• strong acids - ionize 100 in water
• HCl, HBr, HI, H2SO4, HNO3, HClO4
• strong bases - ionize 100 in water
• LiOH, NaOH, KOH, RbOH, CsOH,
• Ca(OH)2, Sr(OH)2, Ba(OH)2

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Arrhenius Theory

• total ionic equation for strong acid with strong
  base

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Arrhenius Theory

• net ionic equation for strong acid with strong
  base

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Acid-Base Theories

• The most general theory for common aqueous acids
  and bases is the BRØNSTED - LOWRY theory
• ACIDS DONATE H IONS
• BASES ACCEPT H IONS

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Acid-Base Theories

• ACIDS DONATE H IONS
• BASES ACCEPT H IONS

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Brønsted-Lowry Acid-Base Theory

• differences between Arrhenius Brønsted-Lowry
  theories
• reaction does not have to occur in an aqueous
  solution
• bases do not have to be hydroxides
• for example- ammonia is not a hydroxide

NH3 H2O ?? NH4 OH-
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Hydronium Ion

• The hydrated hydrogen ion or hydronium ion gives
  aqueous solutions of acids their characteristic
  acidic properties.
• H2O H ?? H3O

hydronium ion
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Hydrated Hydrogen Ion

• H(aq) is really H(H2O)n
• n is a small integer 7?
• H3O is usually used where n 1
• H3O ? H

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Acid-Base Characteristics

• Solution Type Relationship
• Acid H gt OH-
• Neutral H OH-
• Base H lt OH-

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BrønstedLowry Acids

• An acid is a proton donor.

HNO3 H2O ? H3O NO3-
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BrønstedLowry Bases

• A base is a proton acceptor.

NH3 H2O ?? NH4 OH-
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BrønstedLowry Acids and Bases

• The Brønsted definition means NH3 is a BASE in
  water and water is itself an ACID.

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BrønstedLowry Acids and Bases

• An acidbase reaction is the transfer of a proton
  from an acid to a base.
• HCl H2O ? H3O Cl-

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BrønstedLowry Acids and Bases

• When an acid gives up a proton, a conjugate base
  is formed that is capable of accepting a proton.

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BrønstedLowry Acids and Bases

• HF H2O ?? H3O F-

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Conjugate Acid-Bases

• Conjugate acid-base pairs are a reactant and a
  product that differ by a proton, H.

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Conjugate Acid-Bases

• Conjugate acid-base pairs are a reactant and a
  product that differ by a proton, H.

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Conjugate Acid-Bases

• Every acid has a conjugate base, formed by the
  removal of a proton from the acid.
• Every base has a conjugate acid associated with
  it, formed by the addition of a proton to the
  base.
• Thus H3O is the conjugate acid of H2O.

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Conjugate Acid-Bases

• HNO2 H2O ?? H3O NO2-

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Conjugate Acid-Bases
NH3 H2O ?? NH4 OH-
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Conjugate AcidBase Strengths

• The more readily a substance gives up a proton,
  the less readily its conjugate base accepts a
  proton.
• The more readily a base accepts a proton, the
  less readily its conjugate acid gives up a
  proton.

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Conjugate AcidBase Strengths

• The stronger an acid, the weaker its conjugate
  base.
• The weaker an acid, the stronger its conjugate
  base.

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Conjugate AcidBase Strengths
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Ampholytes

• A substance capable of being an acid or a base is
  amphoteric.
• H2O H2O ?? H3O OH-

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Bronsted-Lowry Acid-Base Theory

• water can be either an acid or base in
  Bronsted-Lowry theory
• amphoteric - species that can be either an acid
  or base
• amphiprotic - proton transfer reactions that
  species behave as either an acid or base