Mr. Bouyer
Day 1 | Day 2 | Day 3 - 4 | Lab 1 | Lab 2 | Skills Test

Use the three acid-base theories to identify acids and bases under different conditions. Write the names of binary acids. Write the names of ternary acids. Write the anhydrous form of ternary acids. Predict whether an oxide is an acid anhydride or a basic anhydride. Use the formula of an acid to determine if it is strong or weak. Use factor-label for titration calculations.

To dilute an acid, always add the acid to water. Never add water to acid. Adding water to acid may result in a spattering effect similar to hot grease popping.

There are three "theories" used to define acids and bases. Each of these theories focuses on a slightly different property. As you go down the list, the definition broadens to include a wider range of substances.

1. Arrhenius Theory:
   • Acid - produces hydrogen ions, H ⁺ in water solution.
     • In an equation, the positive part of a Arrhenius acid will be hydrogen.
   • Base - produces hydroxide ions, OH ^- in water solution.
     • In an equation, the negative part of a Arrhenius base will be hydroxide.
   • Acids and bases are thought of as electrolytes. When each dissolves, it ionizes to release the appropriate ion.
   • While this is not completey accurate, it is a good description of those chemicals we call acids and bases.

   • Practice Problems:

   Each of the following unbalanced equations represents a reaction between a Arrhenius acid and base. Identify those in each reaction: H2CO3 + NH4OH (NH4)2CO3 + H2O KOH + H3PO4 K3PO4 + H2O HF + NaOH NaF + H2O Ba(OH)2 + HNO2 Ba(NO2)2 + H2O

   

2. Bronsted - Lowery Theory:
   • Acid - proton donor.
     • In an equation, a Bronsted - Lowery acid must have hydrogen in its formula.
   • Base - proton acceptor.
     • A Bronsted - Lowery base is hard to generalize for all equations. It may be a negative ion. You may have to look at the products. Find one that contains hydrogen. If the negative part of this product was in a reactant that did not contain hydrogen, that reactant is most likely the base.
   • This theory focuses on the action of protons in reactions. Since protons are in the nucleus of an atom, the hydrogen ion is the only source of protons in a normal chemical reaction.
   • The definition of acids and bases is broadened because no specific ions must be formed, but hydrogen is needed in the reaction to produce the proton.
   • Three important terms are used in association with this theory:
     • Conjugate base - the particle that remains after an acid gives up a proton.
     • Conjugate acid - the particle formed when a base accepts a proton.
       HCl + H₂O Cl ^- + H₃O⁺
       Acid + Base Conjugate Base + Conjugate Acid

     • Hydronium ion - formed by a hydrogen ion and a water molecule - H₃O⁺

       Since a hydrogen ion is nothing more than a proton (a bare positive charge), when formed, this proton is immediately attracted to a polar water molecule forming a hydronium ion. For this reason, hydrogen ions never actually exist in water solution.

   • Practice Problems:

   Each of the following unbalanced equations represents a reaction between a Bronsted - Lowery acid and base. Identify those in each reaction: CaCO3 + HCl CaCl2 + H2CO3 H2S + NO3 - S + NO IO3- + H2S I2 + SO3-2 H2SeO3 + Br - Se + Br2

   

3. Lewis Theory:
   • Acid - electron-pair acceptor.
     • In an equation, a Lewis acid gets more negative from the left side to the right.
   • Base - electron-pair donor.
     • In an equation, a Lewis base gets more positive from the left side to the right.
   • This theory is the broadest of all.
   • According to this theory, any reaction involving the exchange of a pair of electrons will have an acid and base.
   • Important terms associated with this theory are:
     • Complex ion - a central positive ion surrounded by bonded ligands.
       • The central ion has empty orbitals and can act as an electron pair acceptor, (Lewis Acid).
     • Ligands - a negative ion or polar molecule bonded to the central ion in a complex.
       • Ligands have unshared electron pairs to donate, (Lewis Base).

   • Practice Problems:

   Each of the following unbalanced equations represents a reaction between a Lewis acid and base. Identify those in each reaction: Cl - + Br2 Cl2 + Br - Mn + Co+2 Mn+2 + Co Cl2 + Sn+2 Cl - + Sn+4 Fe+2 + ClO3 - Fe+3 + Cl -

   

Homework Assignment 241:
This assignment must be turned in by the beginning of class tomorrow to receive credit.
Scoring criteria

1. Why are hydrogen ions NEVER found in an aqueous solution?

2. HCN_(aq) + SO₄^-2_(aq) HSO₄^-_(aq) + CN ^-_(aq)
   1. What is the Bronsted - Lowery acid in this equation?
   2. What is the Bronsted - Lowery base in this equation?
   3. What is the conjugate acid in this equation?
   4. What is the conjugate base in this equation?

3. 2NH₃ + Ag⁺ Ag(NH₃)₂⁺
   1. What is the Lewis acid in this equation?
   2. What is the Lewis base in this equation?

4. O^-2 + SO₃ SO₄^-2
   In this equation, the O^-2 is the Lewis base and the SO₃ is the Lewis acid.
   1. Draw the electron dot diagram for the acid.
   2. Draw the electron dot diagram for the base.
   3. Draw the electron dot diagram for the product, SO₄^-2

Day 2

Binary acids: made up of only two elements - hydrogen and one other element.

• Naming binary acids:
  • Begin with the prefix hydro.
  • Determine the "stem" - part of the name of the element that combines with hydrogen.
  • Add the suffix ic.

  Examples:

  • HCl - hydro chlor ic - hydrochloric acid
  • HBr - hydro brom ic - hydrobromic acid

• Naming ternary acids:
  • Determine the "stem" - part of the name of the third element.
  • The most common acid is given the suffix ic.
  • Add the prefix per for the acid with one more oxygen.
  • The suffix ous is given to the acid with one less oxygen.
  • Add the prefix hypo for the acid with two less oxygen atoms.

  Examples:

  • HClO₄ - per chlor ic - perchloric acid - one more oxygen atom.
  • HClO₃ - chlor ic - chloric acid - the most common form of the acid.
  • HClO₂ - chlor ous - chlorous acid - one less oxygen atom.
  • HClO - hypo chlor ous - hypochlorous acid - two less oxygen atoms.

• Amphoteric - a substance that acts as either acid or base, depending on what it reacts with.
  • Water is the most common amphoteric substance. In the presence of a proton donor, it acts like a base. In the presence of a proton acceptor, it acts like an acid.

• Anhydrous - without water.
  • Anhydrides are substances that have had water removed.
  • Example: Taking the water out of Ba(OH)₂ leaves BaO.
  • Practice Problems: write the anhydrous form of the following
    1. H₂SO₃
    2. H₂C₂O₄
    3. H₃PO₄
    4. H₄C₂O₂
       

• Acid anhydride - an oxide that produces an acid when dissolved in water.
  • Oxides of nonmetals are acid anhydrides.
  • Example: SO₂ + H₂O H₂SO₃ (an acid)
  • Practice Problems: write the formula of the compound formed when these are dissolved in water.
    1. P₂O₃
    2. NO₂