Aqueous Solutions: An Introduction to Chemical Reactions in Water - Prof. Joel Caughran, Study notes of Chemistry

Download Aqueous Solutions: An Introduction to Chemical Reactions in Water - Prof. Joel Caughran and more Study notes Chemistry in PDF only on Docsity! 6 Some Types of Chemical Reactions 2 Chapter Six Goals 1. Aqueous Solutions: An Introduction 2. Reactions in Aqueous Solutions Naming Some Inorganic Compounds 5. Naming Binary Compounds 6. Naming Ternary Acids and Their Salts Classifying Chemical Reactions 7. Oxidation-Reduction Reactions: An Introduction 8. Combination Reactions 9. Decomposition Reactions 10. Displacement Reactions 11. Metathesis Reactions 12. Summary of Reaction Types 13. Synthesis Question 5 Aqueous Solutions: An Introduction Strong electrolytes • Examples: – Strong soluble acids: HCl, HNO3, etc. – Strong soluble bases: NaOH, KOH, etc. – Soluble ionic salts: NaCl, KBr, etc. • Ionize nearly 100% in dilute aqueous solutions 6 Aqueous Solutions: An Introduction Weak electrolytes • Examples: – Weak acids: CH3COOH, HF, (COOH)2 – Weak bases: NH3, Fe(OH)2 – Some insoluble covalent salts • Ionize much less than 100% in dilute aqueous solutions 7 Aqueous Solutions: An Introduction Strong and Weak Acids • Acids are substances that generate H+ in aqueous solutions. • Strong acids ionize 100% in water.       - aqaq %100 g Cl H HCl    10 Aqueous Solutions: An Introduction Strong Acids and Their Anions Acid Anion Name 1. HCl Cl- chloride ion 2. HBr Br- bromide ion 3. HI I- iodide ion 4. HNO3 NO3- nitrate ion 5. H2SO4 SO42- sulfate ion 6. HClO3 ClO3- chlorate ion 7. HClO4 ClO4- perchlorate ion 11 Aqueous Solutions: An Introduction • Weak acids ionize significantly less than 100% in water. – Typically ionize 10% or less! 12 Aqueous Solutions: An Introduction Some Common Weak Acids and Their Anions Formula Name 1. HF hydrofluoric acid 2. CH3COOH acetic acid (vinegar) 3. HCN hydrocyanic acid 4. HNO2 nitrous acid 5. H2CO3 carbonic acid (soda water) 6. H2SO3 sulfurous acid 7. H3PO4 phosphoric acid 8. (COOH)2 oxalic acid 15 Aqueous Solutions: An Introduction • All weak inorganic acids ionize reversibly or in equilibrium reactions. – This is why they ionize less than 100%. • CH3COOH – structure of acetic acid C OH O CH3 16 Aqueous Solutions: An Introduction • Correct chemical symbolism for equilibrium reactions         aq - aq3 7% 3 H + COOCH COOHCH 17 Aqueous Solutions: An Introduction Strong Bases, Insoluble Bases, and Weak Bases • Characteristic of common inorganic bases is that they produce OH- ions in solution. 20 Aqueous Solutions: An Introduction Insoluble or sparingly soluble bases – Ionic compounds that are insoluble in water, consequently, not very basic. Formula Name 1. Cu(OH)2 copper (II) hydroxide 2. Fe(OH)2 iron (II) hydroxide 3. Fe(OH)3 iron (III) hydroxide 4. Zn(OH)2 zinc (II) hydroxide 5. Mg(OH)2 magnesium hydroxide 21 Aqueous Solutions: An Introduction • Weak bases are covalent compounds that ionize slightly in water. • Ammonia is most common weak base – NH3 22 Aqueous Solutions: An Introduction • Weak bases are covalent compounds that ionize slightly in water. • Ammonia is most common weak base – NH3         - (aq)aq42g3 OH + NH OH + NH  25 Aqueous Solutions: An Introduction 5) Common sulfates are water soluble. – Exceptions – PbSO4, BaSO4, & HgSO4 – Moderately soluble – CaSO4, SrSO4, & Ag2SO4 6) Common metal hydroxides are water insoluble. – Exceptions – LiOH, NaOH, KOH, RbOH & CsOH 26 Aqueous Solutions: An Introduction 7) Common carbonates, phosphates, and arsenates are water insoluble. – CO32-, PO43-, & AsO43- – Exceptions- IA metals and NH4+ BaCO3 is moderately soluble – Moderately soluble – MgCO3 8) Common sulfides are water insoluble. – Exceptions – IA metals and NH4+ plus IIA metals 27 Reactions in Aqueous Solutions • Symbolic representation of what is happening at the laboratory and molecular levels in aqueous solutions. – Copper reacting with silver nitrate. • Laboratory level 30 Reactions in Aqueous Solutions • Another example of aqueous reactions. – Sodium chloride reacting with silver nitrate. • Symbolic representation        aq3saqaq3 NaNOAgClNaCl AgNO  31 Reactions in Aqueous Solutions There are three ways to write reactions in aqueous solutions. 1. Molecular equation – Show all reactants & products in molecular or ionic form 2. Total ionic equation – Show the ions and molecules as they exist in solution (s)(aq)4(aq)4(s) Cu + ZnSO CuSO + Zn          (s) -2 aq4 2 aq -2 aq4 2 aq(s) Cu +SO+ ZnSO+ Cu+Zn   32 Reactions in Aqueous Solutions 3. Net ionic equation – Shows ions that participate in reaction and removes spectator ions. • Spectator ions do not participate in the reaction. 35 Naming Some Inorganic Compounds • Binary compounds are made of two elements. – metal + nonmetal = ionic compound – nonmetal + nonmetal = covalent compound • Name the more metallic element first. – Use the element’s name. • Name the less metallic element second. – Add the suffix “ide” to the element’s stem. 36 Naming Some Inorganic Compounds Nonmetal Stems Element Stem • Boron bor • Carbon carb • Silicon silic • Nitrogen nitr • Phosphorus phosph • Arsenic arsen • Antimony antimon 37 Naming Some Inorganic Compounds • Oxygen ox • Sulfur sulf • Selenium selen • Tellurium tellur • Phosphorus phosph • Hydrogen hydr 40 Naming Some Inorganic Compounds • LiBr lithium bromide • MgCl2 magnesium chloride • Li2S lithium sulfide • Al2O3 aluminum oxide • Na3P You do it! 41 Naming Some Inorganic Compounds • LiBr lithium bromide • MgCl2 magnesium chloride • Li2S lithium sulfide • Al2O3 aluminum oxide • Na3P sodium phosphide • Mg3N2 You do it! 42 Naming Some Inorganic Compounds • LiBr lithium bromide • MgCl2 magnesium chloride • Li2S lithium sulfide • Al2O3 aluminum oxide • Na3P sodium phosphide • Mg3N2 magnesium nitride Notice that binary ionic compounds with metals having one oxidation state (representative metals) do not use prefixes or Roman numerals. 45 Naming Some Inorganic Compounds • Compound Old System Modern System • FeBr2 ferrous bromide iron(II) bromide • FeBr3 ferric bromide iron(III) bromide • SnO stannous oxide tin(II) oxide • SnO2 stannic oxide tin(IV) oxide • TiCl2 You do it! 46 Naming Some Inorganic Compounds • Compound Old System Modern System • FeBr2 ferrous bromide iron(II) bromide • FeBr3 ferric bromide iron(III) bromide • SnO stannous oxide tin(II) oxide • SnO2 stannic oxide tin(IV) oxide • TiCl2 titanous chloride titanium(II) chloride • TiCl3 You do it! 47 Naming Some Inorganic Compounds • Compound Old System Modern System • FeBr2 ferrous bromide iron(II) bromide • FeBr3 ferric bromide iron(III) bromide • SnO stannous oxide tin(II) oxide • SnO2 stannic oxide tin(IV) oxide • TiCl2 titanous chloride titanium(II) chloride • TiCl3 titanic chloride titanium(III) chloride • TiCl4 You do it! 50 Naming Some Inorganic Compounds • KOH potassium hydroxide • Ba(OH)2 barium hydroxide • Al(OH)3 aluminum hydroxide • Fe(OH)2 iron (II) hydroxide • Fe(OH)3 You do it! 51 Naming Some Inorganic Compounds • KOH potassium hydroxide • Ba(OH)2 barium hydroxide • Al(OH)3 aluminum hydroxide • Fe(OH)2 iron (II) hydroxide • Fe(OH)3 iron (III) hydroxide • Ba(CN)2 You do it! 52 Naming Some Inorganic Compounds • KOH potassium hydroxide • Ba(OH)2 barium hydroxide • Al(OH)3 aluminum hydroxide • Fe(OH)2 iron (II) hydroxide • Fe(OH)3 iron (III) hydroxide • Ba(CN)2 barium cyanide • (NH4)2S You do it! 55 Naming Some Inorganic Compounds • Binary Acids are binary compounds consisting of hydrogen and a nonmetal. • Compounds are usually gases at room temperature and pressure. – Nomenclature for the gaseous compounds is hydrogen (stem)ide. • When the compounds are dissolved in water they form acidic solutions. – Nomenclature for the acidic solutions is hydro (stem)ic acid. 56 Naming Some Inorganic Compounds • Formula Name Aqueous Solution • HF hydrogen fluoride hydrofluoric acid • HCl hydrogen chloride hydrochloric acid • HBr hydrogen bromide hydrobromic acid • H2S You do it! 57 Naming Some Inorganic Compounds • Formula Name Aqueous solution • HF hydrogen fluoride hydrofluoric acid • HCl hydrogen chloride hydrochloric acid • HBr hydrogen bromide hydrobromic acid • H2S hydrogen sulfide hydrosulfuric acid 60 Naming Some Inorganic Compounds • Formula Name • CO carbon monoxide • CO2 carbon dioxide • SO3 sulfur trioxide • OF2 oxygen difluoride • P4O6 tetraphosphorus hexoxide • P4O10 You do it! 61 Naming Some Inorganic Compounds • Formula Name • CO carbon monoxide • CO2 carbon dioxide • SO3 sulfur trioxide • OF2 oxygen difluoride • P4O6 tetraphosphorus hexoxide • P4O10 tetraphosphorus decoxide 62 Naming Some Inorganic Compounds • The oxides of nitrogen illustrate why covalent compounds need prefixes and ionic compounds do not. • Formula Old Name Modern Name • N2O nitrous oxide dinitrogen monoxide • NO nitric oxide nitrogen monoxide • N2O3 nitrogen trioxide dinitrogen trioxide • NO2 nitrogen dioxide nitrogen dioxide • N2O4 nitrogen tetroxide dinitrogen tetroxide • N2O5 nitrogen pentoxide dinitrogen pentoxide 65 Naming Some Inorganic Compounds • VIA sulfuric acid H2SO4 selenic acid H2SeO4 telluric acid H6TeO6 • VIIA chloric acid HClO3 bromic acid HBrO3 iodic acid HIO3 66 Naming Some Inorganic Compounds • Salts are formed by the reaction of the acid with a strong base. • Acid Salt • HNO2 NaNO2 nitrous acid sodium nitrite • HNO3 NaNO3 nitric acid sodium nitrate • H2SO3 Na2SO3 sulfurous acid sodium sulfite 67 Naming Some Inorganic Compounds • Acid Na Salt • H2SO4 You do it! 70 Naming Some Inorganic Compounds • Acid Na salt • H2SO4 Na2SO4 sulfuric acid sodium sulfate • HClO2 NaClO2 chlorous acid sodium chlorite • HClO3 NaClO3 chloric acid sodium chlorate 71 Naming Some Inorganic Compounds • There are two other possible acid and salt combinations. • Acids that have a higher oxidation state than the “ic” acid are given the prefix “per”. – These acids and salts will have one more O atom than the “ic” acid. • Acids that have a lower oxidation state than the “ous” acid are given the prefix “hypo”. – These acids and salts will have one less O atom than the “ous” acid. 72 Naming Some Inorganic Compounds • Illustrate this series of acids and salts with the Cl ternary acids and salts. • Acid Na Salt • HClO NaClO hypochlorous acid sodium hypochlorite • HClO2 NaClO2 chlorous acid sodium chlorite • HClO3 NaClO3 chloric acid sodium chlorate • HClO4 NaClO4 perchloric acid sodium perchlorate 75 Naming Some Inorganic Compounds • K2HPO4 Old system potassium biphosphate Modern system potassium hydrogen phosphate 76 Naming Some Inorganic Compounds • Basic Salts are analogous to acidic salts. – The salts have one or more basic hydroxides remaining in the compound. • Basic salts are formed by acid-base reactions with insufficient amounts of the acid to react with all of the hydroxide ions. • Use prefixes to indicate the number of hydroxide groups. 77 Naming Some Inorganic Compounds • Ca(OH)Cl – calcium monohydroxy chloride • Al(OH)Cl2 – aluminum monohydroxy chloride • Al(OH)2Cl You do it! • aluminum dihydroxy chloride 80 Oxidation-Reduction Reactions: An Introduction • Two examples of oxidation-reduction or redox reactions. • KMnO4 and Fe2+ – Fe2+ is oxidized to Fe3+ – MnO41- is reduced to Mn2+• Combustion reactions are redox reactions • Combustion of Mg – Mg is oxidized to MgO – O2 is reduced to O2- 81 Oxidation-Reduction Reactions: An Introduction • Example 4-2: Write and balance the formula unit, total ionic, and net ionic equations for the oxidation of sulfurous acid to sulfuric acid by oxygen in acidic aqueous solution. • Formula unit equation • Total ionic equation You do it!      aq42g2aq32 SO H2 O SO H2        24(aq)(aq)g2aq32 SO 2 H 4 O SOH 2 82 Oxidation-Reduction Reactions: An Introduction • Net ionic equation You do it! • Which species are oxidized and reduced? • Identify the oxidizing and reducing agents. You do it!       24(aq)(aq)g2aq32 SO 2 H 4 O SOH 2 85 Combination Reactions 1. Element + Element  Compound A. Metal + Nonmetal  Binary Ionic Compound      sg2s NaCl 2ClNa 2  86 Combination Reactions 1. Element + Element  Compound A. Metal + Nonmetal  Binary Ionic Compound      sg2s MgO 2OMg 2  87 Combination Reactions 1. Element + Element  Compound A. Metal + Nonmetal  Binary Ionic Compound      s32s AlBr 2 Br3Al 2   90 Combination Reactions 1. Element + Element  Compound B. Nonmetal + Nonmetal  Covalent Binary Compound • Can control which product is made with the reaction conditions.       chlorine limitedin AsCl 2 Cl 3As 2 s3g2s        chlorine excessin AsCl 2 Cl 5As 2 s5g2s  91 Combination Reactions 1. Element + Element  Compound B. Nonmetal + Nonmetal  Covalent Binary Compound • Can control which product is made with the reaction conditions.       fluorine limitedin SeF F 2Se s4g2s        fluorine excessin SeF F 3Se g6g2s  92 Combination Reactions 2. Compound + Element  Compound      s5g2s3 AsClClAsCl       g6g2s4 SFFSF  95 Decomposition Reactions • Decomposition reactions occur when one compound decomposes to form: 1. Two elements 2. One or more elements and one or more compounds 3. Two or more compounds 96 Decomposition Reactions 1. Compound  Element + Element – decomposition of dinitrogen oxide • decomposition of calcium chloride      g2g2g2 ON 2ON 2        g2 yelectricit 2 ClCaCaCl         2s h s BAg 2AgBr 2 r   decomposition of silver halides 97 Decomposition Reactions 2. Compound  One Element + Compound(s) – decomposition of hydrogen peroxide      g22 or Mn or Feνh aq22 OO H2O H2 3    