Acids and Bases

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Acids and Bases
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Drill 4/23/08

• Write everything you know about acids and bases!

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Drill 4/30/08

• Write the equation for the neutralization
  reaction between carbonic acid and calcium
  hydroxide.

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Properties of Acids (in aq solution)

• Sour taste
• Low pH
• Turn litmus paper red
• Conduct electrical current

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Properties of Bases (in aq solution)

• Bitter taste
• Slippery
• High pH
• Turn litmus paper blue
• Conduct electrical current

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Arrhenius Definition

• Acid substance that releases H ions in aq
  solution
• HCl ? H Cl-
• Base substance that releases OH- ions in aq
  solution
• NaOH ? Na OH-

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Bronsted-Lowry Definition

• As more and more substances were determined to
  have acidic or basic properties, even some
  without obvious H or OH-, a new definition was
  needed.
• Acid proton donor
• Base proton acceptor

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Bronsted-Lowry Definition

• Acid proton donor
• H2O HCl ? H3O1 Cl-1

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Bronsted-Lowry Definition

• Base proton acceptor
• NH3 H2O ? NH4 OH

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Acid-Base Reactions

• Known as a neutralization reaction. Acids and
  bases will react with each other to form water
  and salt.
• HCl NaOH ? H2O NaCl

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Day 2
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Acid Naming Overview

• Binary
• Start with hydro-
• Element
• End with ic acid
• Tertiary
• I ate something, and now I am sick
• If anion ends in ate then the acid ends in ic
• If the anion ends in ite then the acid ends in
  -ous

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Acids Bases Review

• Acid
• substance that releases H ions in aq solution
• Proton donor
• Electron pair acceptor
• Base
• substance that releases OH- ions in aq solution
• Proton acceptor
• Electron pair donator

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Acid Strength

• A stronger acid will transfer MORE protons (H)
  than a weak acid. It will create more hydronium
  ions (H30) in water.
• Hydrochloric acid
• HCl H20 ? H30 Cl-
• Acetic Acid
• CH3COOH H20 ? H30 CH3COO-

More dissociation!
Less dissociation!
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• How do we compare the strength of an acid or a
  base?
• We measure the amount of hydronium ions they
  create (acids) or the amount of hydroxide ions
  they create (bases).using concentration.

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What is concentration?

• Using molarity, it is a measure of moles of
  solute in liters of solution.
• Concentration is measured in WATER!

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H2O is both an acid and a base

• Water is simultaneously donating and accepting
  protons!

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What are the ion concentrations in water?

• The concentrations of H3O and OH- in pure water
  are each 1.0x10-7 mol/L at 25ºC.
• Putting a symbol in brackets is used to signify
  the concentration.
• H30 1.0x10-7 M
• OH- 1.0x10-7 M

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Ionization Constant of water, KW

• KW H30 OH-
• KW (1.0x10-7)(1.0x10-7) 1.0x10-14

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• Acids increase the H30 Whenever H30 is
  greater than OH-, the solution is acidic.
• Bases increase the OH-
• Whenever OH- is greater than H30, the
  solution is basic.

With an increase in H30, some of the H30
ions will react with the OH- ions, reducing OH-
. H30OH- will still 1.0x10-14
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• Concentration values tend to be smallso we use a
  more convenient scale. pH!

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pH pOH 14

• pH A measure of the acidity of a solution. It
  is the negative logarithm of the hydronium ion
  H30 concentration.
• pH -log H30

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pH pOH 14

• pOH A measure of how basic a solution is. It
  is the negative logarithm of the hydroxide OH-
  concentration.
• pOH -log OH-

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• The logarithm base 10 of a number x is the power
  to which 10 must be raised in order to equal x.
• Log 10 x ? Log 100 ?
• 10? x 10 ? 100

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• Remember, our concentrations are SMALL. So we
  are going to be dealing with decimals
• Log 10 x ? Log .001 ?
• 10? x 10 ? .001

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H 1.00 x 10-3 0.001 pH -log H pH
-log (1.00 x 10-3) pH 3
To determine pH from a concentration where 1 is
the only digit, write the concentration in
scientific notation. The exponent will be the pH.
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• For a base, you do the same thing except remember
  that you are solving for pOH first

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