1.1. To learn about some of the factors that cause reactions to To learn about some of the factors that cause reactions to occur occur

2.2. To learn to identify the solid that forms in a precipitation To learn to identify the solid that forms in a precipitation reaction reaction

3.3. To learn to write molecular, complete ionic, and net ionic To learn to write molecular, complete ionic, and net ionic equations equations

8.1 ObjectivesChapter 8Chapter 8

A. A. Predicting Whether a Predicting Whether a Reaction Will Occur Reaction Will Occur

Four driving forces favor chemical change. Four driving forces favor chemical change. Formation of a solidFormation of a solid Formation of water Formation of water Transfer of electrons Transfer of electrons Formation of a gas Formation of a gas

B. B. Reactions in Which a Solid Reactions in Which a Solid Forms Forms

A reaction in which a A reaction in which a solid forms is called a solid forms is called a precipitation reactionprecipitation reaction.. Solid = Solid = precipitateprecipitate

http://www.youtube.com/watch?v=pFovlKpPCbI

The ions separate and move around independently. The ions separate and move around independently.

B. B. Reactions in Which a Solid Forms Reactions in Which a Solid Forms What Happens When an Ionic Compound Dissolves in

Water?

B. B. Reactions in Which a Solid Forms Reactions in Which a Solid Forms

What Happens When an Ionic Compound Dissolves in Water?

KK22CrOCrO44(aq)(aq) + Ba(NO + Ba(NO33))22(aq)(aq) Products Products

NaClNaCl(s)(s) + H + H22OO(l)(l) Na Na++ + Cl + Cl-- + H + H22OOhttp://www.youtube.com/watch?v=EBfGcTAJF4o

• Determine the possible products from the ions in the reactants.

• In our example

K2CrO4(aq) + Ba(NO3)2(aq) Products

The possible ion combinations are:

B. B. Reactions in Which a Solid Forms Reactions in Which a Solid Forms How to Decide What Products Form

B. B. Reactions in Which a Solid Forms Reactions in Which a Solid Forms

How to Decide What Products Form

• Decide which is most likely to be the yellow solid formed in the reaction.

• K2CrO4(aq) reactant

Ba(NO3)2(aq) reactant

• The possible combinations are KNO3 and BaCrO4.

– KNO3 white solid

– BaCrO4 yellow solid

Reading!Reading!

ReadRead in 8.1, the section title in 8.1, the section title Using Using Solubility Rules Solubility Rules (pg 244-245)(pg 244-245) StudyStudy the solubility rules, the solubility rules, Table 8.1Table 8.1 and and

Figure 8.3Figure 8.3 (pg 245)(pg 245)

Also, Also, readread and and examineexamine Example 8.1Example 8.1 (pg (pg 246-247)246-247)

B. B. Reactions in Which a Solid Forms Reactions in Which a Solid Forms Using Solubility Rules: Table

B. B. Reactions in Which a Solid Forms Reactions in Which a Solid Forms

• Predicting Precipitates

Using Solubility Rules

– Soluble solid – Insoluble solid – Slightly soluble solid

B. B. Reactions in Which a Solid Forms Reactions in Which a Solid Forms Review!

How to predict precipitates when solutions of 2 Ionic Compounds are mixed:

Step 1: Write the reactants as they actually exist before any reaction occurs. Remember that when a salt dissolves, its ions separate.

Step 2: Consider the various solids that could form. To do this, simply exchange the anions of the added salts.

Step 3: Use the solubility rules (Table 8.1 and your chart) to decide whether a solid forms and, if so, to predict the identity of the solid.

C. C. Describing Reactions in Aqueous Describing Reactions in Aqueous Solutions Solutions

Three types of equations:Three types of equations: Molecular (formula) equation Molecular (formula) equation complete formulas of all reactants and productscomplete formulas of all reactants and products Complete ionic equation Complete ionic equation

all strong electrolytes are shown as ionsall strong electrolytes are shown as ions Net ionic equation Net ionic equation only those components of the solution that only those components of the solution that

undergo a changeundergo a changeSpectator ion (those that remain unchanged) Spectator ion (those that remain unchanged)

not shown in the net ionic equationnot shown in the net ionic equation

ExampleExampleNaClNaCl(aq)(aq) + AgNO + AgNO33(aq)(aq) → AgCl→ AgCl(s)(s) + NaNO + NaNO33(aq)(aq)

Molecular equation:Molecular equation: NaClNaCl(aq)(aq) + AgNO + AgNO33(aq)(aq) → AgCl→ AgCl(s)(s) + NaNO + NaNO33(aq)(aq)

Complete Ionic Equation:Complete Ionic Equation: NaNa++(aq) + (aq) + ClCl--(aq)(aq) + Ag + Ag++(aq)(aq) + NO + NO3 3

--(aq) (aq) → AgCl→ AgCl(s)(s) + +

NaNa++(aq) + (aq) + NONO3 3 --(aq) (aq)

Net Ionic Equation:Net Ionic Equation: ClCl--(aq)(aq) + Ag + Ag++(aq)(aq) → AgCl→ AgCl(s)(s)

1.1. To learn about reactions between strong acids and strong To learn about reactions between strong acids and strong basesbases

2.2. To learn about the reaction between a metal and a To learn about the reaction between a metal and a nonmetalnonmetal

3.3. To understand how electron transfer produces a chemical To understand how electron transfer produces a chemical reaction reaction

8.2 Objectives

A. A. Reactions That Form Water: Acids Reactions That Form Water: Acids and Bases and Bases

Arrhenius Acids and Bases

A strong acid is one in which virtually every A strong acid is one in which virtually every molecule dissociates (ionizes) in water to an Hmolecule dissociates (ionizes) in water to an H++ ion ion and an anion.and an anion.

A strong base is a metal hydroxide that is A strong base is a metal hydroxide that is completely soluble in water, giving separate OHcompletely soluble in water, giving separate OH ions and cations. ions and cations.

A. A. Reactions That Form Water: Reactions That Form Water: Acids and Bases Acids and Bases

Arrhenius Acids and Bases

– Most common NaOH, KOH

A. A. Reactions That Form Water: Acids Reactions That Form Water: Acids and Bases and Bases

Arrhenius Acids and Bases

The products of the reaction of a strong acid and a The products of the reaction of a strong acid and a strong base are water and a salt.strong base are water and a salt.

– Salt Ionic compound• Net ionic equation

– H+(aq) + OH−(aq) H2O(l)

• Reaction of H+ and OH− is called an acid-base reaction. – H+ acidic ion – OH− basic ion

B. B. Reactions of Metals with Reactions of Metals with Nonmetals (Oxidation-Reduction)Nonmetals (Oxidation-Reduction)

• Reactions between metals and nonmetals involve a transfer of electrons from the metal to the nonmetal. – oxidation – reduction reaction

1.1. To learn various classification schemes for reactionsTo learn various classification schemes for reactions

8.3 Objectives

A. A. Ways to Classify Reactions Ways to Classify Reactions Driving forces for a reaction:Driving forces for a reaction: Formation of a solidFormation of a solid

AB + CD AB + CD AD + CB AD + CB

Precipitation reaction Precipitation reaction

Double displacement reaction Double displacement reaction Formation of water Formation of water

HH++(aq)(aq) + OH + OH−−(aq)(aq) H H22OO(l)(l)

Acid-base reaction Acid-base reaction

A. A. Ways to Classify Reactions Ways to Classify Reactions

Driving forces for a reaction:Driving forces for a reaction:

– Transfer of electrons

A. A. Ways to Classify Reactions Ways to Classify Reactions Driving forces for a reaction:Driving forces for a reaction:

– Transfer of electrons– Formation of a Gas

• A + BC B + AC

• Single replacement reaction

Involve oxygen and produce energy so rapidly that a Involve oxygen and produce energy so rapidly that a flame resultsflame results CHCH44(g)(g) + 2O + 2O22(g)(g) CO CO22(g)(g) + 2H + 2H22OO(g)(g) Special class of oxidation-reduction reactions Special class of oxidation-reduction reactions

B. B. Other Ways to Classify Reactions Other Ways to Classify Reactions Combustion Reactions

A synthesis reaction is one in which a compound forms A synthesis reaction is one in which a compound forms from simpler materials.from simpler materials. C(s) + OC(s) + O22(g) (g) CO CO22(g) (g) Special class of oxidation-reduction reactions Special class of oxidation-reduction reactions

B. B. Other Ways to Classify Reactions Other Ways to Classify Reactions

Synthesis (Combination) Reactions

+

A decomposition reaction occurs when a compound is A decomposition reaction occurs when a compound is broken down into simpler substances.broken down into simpler substances. 2H2H22O(l) O(l) 2H2H22(g) + O(g) + O22(g)(g)

B. B. Other Ways to Classify Reactions Other Ways to Classify Reactions

Decomposition Reactions

+

B. B. Other Ways to Classify Other Ways to Classify Reactions Reactions

Summary

http://www.youtube.com/watch?v=tE4668aarck&safety_mode=true&persist_safety_mode=1