Chem 105 Chpt 4 Lsn 10 1 CHAPTER 5 Reactions in Aqueous Solution Turn in homework for Chapter 4 Turn in homework for Chapter 4

Chem 105 Chpt 4 Lsn 10 2 Road Map Where we were Where we were Percent yield Percent yield Chemical equations and chemical analysis Chemical equations and chemical analysis Where we are going Where we are going Review problems Review problems Critical skills: naming common ions, writing electrically neutral formulas/reactions, stoichiometric conversions Critical skills: naming common ions, writing electrically neutral formulas/reactions, stoichiometric conversions Types of reactions Types of reactions

Chem 105 Chpt 4 Lsn 10 3 Determining the Formula of an Unknown Compound: Molecular Formulas

Chem 105 Chpt 4 Lsn 10 4 p.162b

Chem 105 Chpt 4 Lsn 10 5 Chemical Analysis/Equation A dry-cleaning solvent (M = g/mol) that contains C, H, and Cl is suspected to be a cancer-causing agent. When a g sample was studied by combustion analysis, g of CO 2 and g of H 2 O formed. Calculate the molecular formula. A dry-cleaning solvent (M = g/mol) that contains C, H, and Cl is suspected to be a cancer-causing agent. When a g sample was studied by combustion analysis, g of CO 2 and g of H 2 O formed. Calculate the molecular formula. Empirical C 3 H 2 Cl Empirical C 3 H 2 Cl Molecular C 6 H 4 Cl 2 Molecular C 6 H 4 Cl 2

Chem 105 Chpt 4 Lsn 10 6 Are you up to the challenge? Iodine is made by the reaction Iodine is made by the reaction 2 NaIO 3 (aq) + 5 NaHSO 3 (aq)  3 NaHSO 4 (aq) + 2 Na 2 SO 4 (aq) + H 2 O (l) + I 2 3 NaHSO 4 (aq) + 2 Na 2 SO 4 (aq) + H 2 O (l) + I 2 a) Name the two reactants b) If you wish to prepare 1.00 kg of I 2, what mass of NaIO 3 is required? c) What mass of NaHSO 3 ?

Chem 105 Chpt 4 Lsn Aqueous solutions Hyponitriemia Hyponitriemia Electrolytes: aqueous solutions which conduct electricity Electrolytes: aqueous solutions which conduct electricity Strong – complete/nearly complete dissociation Strong – complete/nearly complete dissociation Weak – only partial dissociation Weak – only partial dissociation Figure 5.3, page 179 (know) Figure 5.3, page 179 (know)

Chem 105 Chpt 4 Lsn Precipitation reactions Writing Equations for Aqueous Ionic Reactions Three types of equations are used to represent aqueous ionic reactions: molecular, total ionic, and net ionic equations. molecular equation: shows all reactants and products as if they were intact, undissociated total ionic equation: shows all the soluble ionic substances dissociated into ions. Charges must balance Spectator ions not involved in chemical change. net ionic equation: it eliminates the spectator ions and shows the actual chemical change taking place.

Chem 105 Chpt 4 Lsn 10 9 Practice Problem 10-1 molecular equation Pb(NO 3 ) 2 (aq) + K 2 CrO 4 (aq) → PbCrO 4 (s) + 2 KNO 3 (aq) Write the Total Ionic and Net Ionic equations for Total Net

Chem 105 Chpt 4 Lsn Practice Problem 10-2 Write the Total Ionic and Net Ionic equations for HCl(aq) + NaOH(aq) → NaCl(aq) + H 2 O(l)

Chem 105 Chpt 4 Lsn Practice Problem 10-3 Solutions of iron (III) chloride and potassium hydroxide give iron (III) hydroxide and potassium chloride when combined. Solutions of iron (III) chloride and potassium hydroxide give iron (III) hydroxide and potassium chloride when combined. Write the Write the Molecular equation Molecular equation Total ionic equation Total ionic equation Net ionic equation Net ionic equation

Chem 105 Chpt 4 Lsn – Acids and Bases (know table 5.2) Acid: increases the H + concentration Acid: increases the H + concentration Base: increases the OH - concentration Base: increases the OH - concentration Strong acid: completely dissociates/ionizes Strong acid: completely dissociates/ionizes Weak acid: partial ionization Weak acid: partial ionization

Chem 105 Chpt 4 Lsn Reactions of Acids and Bases An Acid reacting with a base produce a An Acid reacting with a base produce a salt and water Neutralization reaction: a strong acid with a strong base Neutralization reaction: a strong acid with a strong base

Chem 105 Chpt 4 Lsn Lesson summary Calcium chloride and potassium phosphate combine to form calcium phosphate and potassium chloride. Write the molecular equation 3 CaCl 2 (aq) + 2 K 3 PO 4 (aq) → Ca 3 PO 4 (s) + 6 KCl(aq) Write the Total Ionic and Net Ionic equations

Chem 105 Chpt 4 Lsn CaCl 2 (aq) + 2 K 3 PO 4 (aq) → Ca 3 PO 4 (s) + 6 KCl(aq) Write the Total Ionic and Net Ionic equations Combining 5 grams CaCl 2 with 3.5 grams of K 3 PO 4 produced only a 67% yield of KCl. What is the limiting reactant? What mass of product did you make?

Chem 105 Chpt 4 Lsn Next Lesson Chapter 5 Chapter 5 Gas forming reactions Gas forming reactions Classifying reactions Classifying reactions Oxidation reactions Oxidation reactions Measuring concentrations of compounds in solution Measuring concentrations of compounds in solution pH pH Stoichiometry of reactions in aqueous solution Stoichiometry of reactions in aqueous solution

Chem 105 Chpt 4 Lsn Practice Problem 10-4 Write the Total Ionic and Net Ionic equations for CaCl 2 (aq) + Na 2 CO 3 (aq) → CaCO 3 (s) + 2 NaCl(aq)

Chem 105 Chpt 4 Lsn Practice Problem Write the Total Ionic and Net Ionic equations for Zn(s) + H 2 SO 4 (aq) → ZnSO 4 (aq) + H 2 (g)

Chem 105 Chpt 4 Lsn 10 19