Acids, Bases & Salts n Acid Properties : n Sour taste, react with metals to produce hydrogen gas, electrolytes, affect indicators (turns blue litmus paper to red)

Acids, Bases & Salts n Base Properties : n Bitter taste, produce electrolytes, affect indicators (turns red litmus paper to blue)

Acids n Electrolytes: substances that conduct electric current when dissolved in water.

Acids n Indicators: chemical substances that change color based on acid concentration.

Acids n Arrhenius Theory: acids produce H + ions when dissolved (ionized) in water.

Acids n Arrhenius Theory: bases produce OH - ions when dissolved (ionized) in water.

Acids n Dissociation vs. ionization: dissociation is the separation of ions in solution. In ionization, neutral molecules react with water to form ions.

Acids n Bronsted-Lowry Theory: acids donate protons (H + ) in a chemical reaction. n Ex. HCl(g) + H 2 O(l) --> H 3 O + (aq) + Cl - (aq)

Acids n The HCl gas donates a proton to the water molecule, producing the hydronium ion. HCl is considered an acid, water is considered a base.

Acids n Bronsted-Lowry Theory: bases accept protons (H + ) in a chemical reaction. n HCl and Cl - are considered a conjugate acid/base pair.

Acids n Conjugate acid/base pairs: Conjugate base - the particle leftover after the acid donates a proton.

Acids n Conjugate acid/base pairs: Conjugate acid - the particle produced after the base accepts the proton.

Acids n Identify the acid, base, conjugate base and conjugate acid in the following: HNO 3 (aq) + NaOH(aq) --> H 2 O(l) + NaNO 3 (aq).

Acids n Practice problems #1-2, p n What do you want to know?

Acids n Lewis Theory: an acid is any substance that accepts an electron pair. A base is any substance that donates an electron pair. n NH 3 + BF 3 --> NH 3 BF 3

Acids n Use electron dot diagrams to determine if a substance is a Lewis acid or base. n Ex. Classify Cl - as a Lewis acid or base.

Acids n Coordination complexes: molecular ligands (attachments) approach a metal cation and bond using secondary (d-orbital) valance.

Acids n Complex ion formation: ex. Ag + + NH 3 --> ? (coordination number of 2).

Acids n What is the name of [CoCl 2 (NH 3 ) 5 ]Br n Practice Problems #3-8, p Any questions?

Acid Nomenclature n Binary acids: acids consisting of 2 elements. n Ex. HCl n HI n HBr

Acid Nomenclature n Ternary Acids and Bases: acids or bases containing three elements. n Common ternary acid - formed by using H + and a common polyatomic ion.

Acid Nomenclature n Use the polyatomic name and the suffix -ic. n Ex. H 2 SO 4 n HNO 3 n HClO 3

Acid Nomenclature n A ternary acid that is the same as the common acid but with one less oxygen uses the suffix -ous. n Ex. H 2 SO 3 n HClO 2

Acid Nomenclature n A ternary acid that is the same as the common acid but with two less oxygens uses the prefix -hypo and the suffix -ous. n Ex. HClO

Acid Nomenclature n A ternary acid that is the same as the common acid but with one more oxygen uses the prefix -per and the suffix -ic. n Ex. HClO 4

Acid Nomenclature n Common ternary base - formed by using metal and the hydroxide polyatomic ion. n Ex. NaOH, Mg(OH) 2

Acid Nomenclature n Organic acids: carboxylic acids, -COOH n Name the chain and add - oic acid.

Acid Nomenclature n Practice Problems #9-13, p. 580 n Wha?

Acid/Base Behavior n Consider a compound in the form HOX. If X is very electronegative then the H is given up as a proton and it acts as an acid. If not it acts as a base.

Acid/Base Behavior n So, nonmetals tend to form acids, metals tend to form bases when dissolved in water. n Ex. MgO n CO

Acid/Base Behavior n Acidic and Basic Anhydrides: acids and bases that have had water removed. n Ex. Acid anhydride + water --> acid

Acid/Base Behavior n Ex. Acid anhydride + water --> acid n SO 2 + H 2 O --> H 2 SO 3

Acid/Base Behavior n Ex. basic anhydride + water --> base n Na 2 O + H 2 O --> 2 NaOH n Practice problems #14-15 p. 583

Acid/Base Behavior n Acid base strength: not all acids complete ionize in water. That is a lot of the acid or base molecules remain unreacted. n Ex. Ammonia (weak base)

Acid/Base Behavior n Concept review #16-19 p. 584

Salts and Solutions n Salt : an ionic compound that does not consist of H + or OH - n Ex. KCl, MgO (any ionic compound that is not an Arrehnius acid or base)

Neutralization n Neutralization reaction: a acid reacts with a base to produce a salt and water. n Really just a double displacement reaction

Neutralization n Ex. Produce the products and balance the equation for the reaction of the acid HCl and the base AgOH.

Neutralization n Naming salts - who cares? n Ex. Sodium hydrogen carbonate n Ex. Sodium dihydrogen phosphate

Net Ionic Equations n Some ions in a neutralization reaction are considered spectator ions. That is, they are unchanged after the reaction.

Net Ionic Equations n Chemists often write net ionic equations to show only those ions that actually take place in the reaction. Ex. HCl + NaOH

Net Ionic Equations n Polyprotic acids - go through two steps of ionization n Ex. Sulfuric acid

Net Ionic Equations n The binary acids HCl, HBr, and HI are strong acids, the rest are weak. n Ternary acids with 2 or more oxygens versus hydrogens are strong.

Net Ionic Equations n Organic acids are weak. n Polyprotic acids: second step always results in a weak acid n Group 1 and 2 bases are strong.

Net Ionic Equations n Molecules and weak acids and bases are not written in ionic form. n Salts are written in ionic form, oxides and gases are written as molecules.

Net Ionic Equations n Practice problems #23-27 p (in groups - 15 minutes)

Ionization Constant n The K eq for the ionization of a weak acid or base determines the extent that [H 3 O + ] or [OH - ] ions will be produced at equilibrium.

Ionization Constant n K a is the ionization constant of a weak acid. HX + H 2 O H 3 O + + X -. n What is K a for this reaction?

Ionization Constant n K b is the ionization constant of a weak base. NH 3 + H 2 O NH OH -. n What is K b for this reaction?

Ionization Constant n Percent ionization = [amount ionized] / [original acid] x 100% n Problems 28-31, p

Ionization Constant n Common Ion Effect - adding ions that are the same as one of those produced by the ionization of a weak electrolyte …. (more)

Ionization Constant n to a solution of the electrolyte suppresses its ionization. Why???

Ionization Constant n Le Chatelier’s Principle - you are increasing the concentration of products. The system responds to reestablish equilibrium.

Ionization Constant n Problems p