1. Comments on Test 2. Section 16.1A – Acids and Bases 3. Homework: pg 589, #2, 3, 7, 8, 9, 10 Wednesday, March 12, 2008

Acids in your life

Acid Properties Sour Corrosive to metals Electrolytes React with litmus and indicators

Base Properties Bitter Eat through organic material Electrolytes React with litmus paper and indicators Slippery

Arrhenius Definition First person to have some understanding of acids and bases was Svante Arrhenius First person to have some understanding of acids and bases was Svante Arrhenius Acids – produce hydrogen ions in aqueous solutions. Acids – produce hydrogen ions in aqueous solutions. Bases – produce hydroxide ions in aqueous solutions. Bases – produce hydroxide ions in aqueous solutions.

Arrhenius Definition HCl(g) H + (aq) + Cl - (aq) NaOH(s)Na + (aq) + OH - (aq) HNO 3 HC 2 H 3 O 2 KOH

Arrhenius Definition This theory was a major step forward – but somewhat limited. This theory was a major step forward – but somewhat limited. There is only one kind of base in this theory. There is only one kind of base in this theory.

Bronsted Lowry definition Acid – hydrogen ion (proton) donor Acid – hydrogen ion (proton) donor Base – hydrogen ion (proton) acceptor Base – hydrogen ion (proton) acceptor HA(g) + H 2 O(l)  H 3 O + (aq) + A - (aq) acidbase

Bronsted Lowry definition This broadens the definition This broadens the definition Does not need to be in water Does not need to be in water Bases don’t need to contain an OH - Bases don’t need to contain an OH - All acids/bases in the Arrhenius definition are also acids/bases in the Bronsted/Lowry definition. All acids/bases in the Arrhenius definition are also acids/bases in the Bronsted/Lowry definition.

Bronsted Lowry definition HCl(aq) + H 2 O(l)  H 3 O + (aq) + Cl - HCl(aq) + H 2 O(l)  H 3 O + (aq) + Cl - In this equation HA, (general formula for acids) donates the proton to the water and water accepts it. In this equation HA, (general formula for acids) donates the proton to the water and water accepts it. What is the name of H3O+? What is the name of H3O+? Hydronium ion. Hydronium ion. HCl is acid. HCl is acid. Water is the base. Water is the base.

Bronsted Lowry NH 3 (aq) + H 2 O(l)  NH 4 + (aq) + OH - (aq) Baseacidconjugate conjugate acid base Conjugate acid – the particle formed when a base gains an H + ion. Conjugate base – the particle that remains after the acid donates an H + ion.

Bronsted Lowry An acid does not react with it’s conjugate base. It produces a conjugate base. An acid does not react with it’s conjugate base. It produces a conjugate base. A conjugate acid-base pair consists of two substances related by the loss or gain of a single hydrogen ion. A conjugate acid-base pair consists of two substances related by the loss or gain of a single hydrogen ion. How can water attract an extra H? How can water attract an extra H? Has 2 lone pair electrons to attract the H + Has 2 lone pair electrons to attract the H +

Example Which of the following represent conjugate acid-base pairs? A) HClO 4, ClO 4 - B) HCl, ClO - C) H 2 PO 4 -, HPO 4 2- D) HNO 3, NO 3 - A, C, and D A, C, and D