Copyright©2000 by Houghton Mifflin Company. All rights reserved. 1 Reactions Chapter 4.

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Copyright2000 by Houghton Mifflin Company. All rights reserved. *ReactionsChapter 4Copyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Aqueous SolutionsWater is the dissolving medium, or solvent.Copyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Figure 4.1 The Water Molecule is PolarCopyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Some Properties of WaterWater is bent or V-shaped.The O-H bonds are covalent.Water is a polar molecule.Hydration occurs when salts dissolve in water.Copyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Copyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *http://mathinscience.info/teach/k5_science/chemistry/mastering_matter/matter_animations/salt_cystl_watr_mol_web.swfCopyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Figure 4.2Polar Water Molecules Interact with the Positive and Negative Ions of a SaltCopyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Figure 4.3Polar BondCopyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *A Solutedissolves in water (or other solvent)changes phase (if different from the solvent)is present in lesser amount (if the same phase as the solvent)Copyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *A Solventretains its phase (if different from the solute)is present in greater amount (if the same phase as the solute)Copyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *ElectrolytesStrong - conduct current efficientlyNaCl, HNO3Weak - conduct only a small currentvinegar, tap waterNon - no current flowspure water, sugar solutionCopyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Figure 4.5BaCI2 DissolvingCopyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *AcidsStrong acids -dissociate completely to produce H+ in solutionhydrochloric and sulfuric acidWeak acids - dissociate to a slight extent to give H+ in solutionacetic and formic acidCopyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Figure 4.6HCI (aq) is Completely IonizedCopyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Figure 4.8Acetic Acid in WaterCopyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Bases Strong bases - react completely with water to give OH ions.sodium hydroxide Weak bases - react only slightly with water to give OH ions.ammoniaCopyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Molarity Molarity (M) = moles of solute per volume of solution in liters:Copyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Common Terms of Solution Concentration Stock - routinely used solutions prepared in concentrated form. Concentrated - relatively large ratio of solute to solvent. (5.0 M NaCl) Dilute - relatively small ratio of solute to solvent. (0.01 M NaCl)Copyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Figure 4.10Preparation of a Standard SolutionCopyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Types of Double Displacement ReactionsPrecipitation reactionsAgNO3(aq) + NaCl(aq) AgCl(s) + NaNO3(aq)Acid-base reactionsNaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)Oxidation-reduction reactionsFe2O3(s) + Al(s) Fe(l) + Al2O3(s)Copyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Simple Rules for Solubility1.Most nitrate (NO3) salts are soluble.2.Most alkali (group 1A) salts and NH4+ are soluble.3.Most Cl, Br, and I salts are soluble (NOT Ag+, Pb2+, Hg22+)4.Most sulfate salts are soluble (NOT BaSO4, PbSO4, HgSO4, CaSO4)5.Most OH salts are only slightly soluble (NaOH, KOH are soluble, Ba(OH)2, Ca(OH)2 are marginally soluble)6.Most S2, CO32, CrO42, PO43 salts are only slightly soluble. Copyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Describing Reactions in Solution1.Molecular equation (reactants and products as compounds)AgNO3(aq) + NaCl(aq) AgCl(s) + NaNO3(aq)2.Complete ionic equation (all strong electrolytes shown as ions)Ag+(aq) + NO3(aq) + Na+(aq) + Cl(aq) AgCl(s) + Na+(aq) + NO3(aq)Copyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Describing Reactions in Solution (continued)3.Net ionic equation (show only components that actually react)Ag+(aq) + Cl(aq) AgCl(s)Na+ and NO3 are spectator ions.Copyright2000 by Houghton Mifflin Company. All rights reserved. Quick Review Are you Ready?Copyright2000 by Houghton Mifflin Company. All rights reserved. *YesNo1234567891011121314151617Copyright2000 by Houghton Mifflin Company. All rights reserved. When Fe(NO3)2 dissolves in water, what particles are present in the solution?Fe+ and (NO3)2Fe2+ and 2 NO3Fe and 2 NO3Fe and N2 and 3 O21234567891011121314151617Pb(NO3)2 + 2 KI PbI2 + 2 KNO3What is the observable evidence that the above reaction occurs?An explosion.A gas forms.The solution boils.A solid forms.1234567891011121314151617When an acid and a base react to form a salt and water, the reaction is called a(n):cancellation.elimination.neutralization.adduct formation.1234567891011121314151617Which mixture will produce a precipitate? Copyright2000 by Houghton Mifflin Company. All rights reserved. *1.23451234567891011121314151617Copyright2000 by Houghton Mifflin Company. All rights reserved. What is(are) the spectator ion(s) in the following reaction? K+FK+ and F OH and H+OH 1234567891011121314151617Which of the following reactions has the net ionic equation: Reaction 1Reactions 1, 4Reactions 2, 3Reactions 2, 4 Reactions 3, 41234567891011121314151617Copyright2000 by Houghton Mifflin Company. All rights reserved. *Copyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Other ReactionsSingle displacementCombustionSynthesisDecompositionAll of these involve a transfer of electrons and are oxidation-reduction (Redox) reactionsCopyright2000 by Houghton Mifflin Company. All rights reserved. 2009, Prentice-Hall, Inc.Oxidation-Reduction ReactionsAn oxidation occurs when an atom or ion loses electrons.A reduction occurs when an atom or ion gains electrons.One cannot occur without the other.Copyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Rules for Assigning Oxidation States1. Oxidation state of an atom in an element = 02. Oxidation state of monatomic ion = charge3. Oxygen = 2 in covalent compounds (except in peroxides where it = 1)4. H = +1 when bonded to nonmetal; -1 when bonded to metalCopyright2000 by Houghton Mifflin Company. All rights reserved. 5. Fluorine = 1 in compoundsThe other halogens have an oxidation number of 1 when they are negative; they can have positive oxidation numbers, however, most notably in oxyanions (polyatomic ions with oxygen)6. Sum of oxidation states = 0 in compounds Sum of oxidation states = charge of the ionCopyright2000 by Houghton Mifflin Company. All rights reserved. *Copyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Redox Reactions - TermsOxidation loss of electrons (increase in oxidation number)Reduction gain of electrons (decrease in oxidation number)Oxidizing agent the compound that is the electron acceptorReducing agent the compound that is the electron donorCopyright2000 by Houghton Mifflin Company. All rights reserved. When an atom undergoes reduction, it _______ electrons.gainslosesretainsbalances1234567891011121314151617What is the oxidation number of sulfur in the following compound? SO2Copyright2000 by Houghton Mifflin Company. All rights reserved. *-4+4-2+21234567891011121314151617Copyright2000 by Houghton Mifflin Company. All rights reserved. What is the oxidation number of oxygen in the following compound? MgOCopyright2000 by Houghton Mifflin Company. All rights reserved. *-4+4-2+21234567891011121314151617Copyright2000 by Houghton Mifflin Company. All rights reserved. What is the oxidation number of Manganese in the following compound? MnO2Copyright2000 by Houghton Mifflin Company. All rights reserved. *-4+4-2+21234567891011121314151617Copyright2000 by Houghton Mifflin Company. All rights reserved. What is the oxidation number of Fluorine in the following compound? F2Copyright2000 by Houghton Mifflin Company. All rights reserved. *-1+10-21234567891011121314151617Copyright2000 by Houghton Mifflin Company. All rights reserved. What is the oxidation number of Sulfur in the following compound? SO42-Copyright2000 by Houghton Mifflin Company. All rights reserved. *+8+6-2+41234567891011121314151617Copyright2000 by Houghton Mifflin Company. All rights reserved. What is the oxidation number of manganese in the permanganate ion?Copyright2000 by Houghton Mifflin Company. All rights reserved. *+8+6-6+71234567891011121314151617Copyright2000 by Houghton Mifflin Company. All rights reserved. What is the oxidation number of nitrogen in the nitrite ion?Copyright2000 by Houghton Mifflin Company. All rights reserved. *+3+5-5+21234567891011121314151617Copyright2000 by Houghton Mifflin Company. All rights reserved. What is reduced in the following equation?Al + Cu(NO3)2 Cu + Al(NO3)3Copyright2000 by Houghton Mifflin Company. All rights reserved. *AlCuCu(NO3)2Al(NO3)31234567891011121314151617Copyright2000 by Houghton Mifflin Company. All rights reserved. What is oxidized in the following equation?Al + Cu(NO3)2 Cu + Al(NO3)3Copyright2000 by Houghton Mifflin Company. All rights reserved. *AlCuCu(NO3)2Al(NO3)3Copyright2000 by Houghton Mifflin Company. All rights reserved. What is reducing agent in the following equation?Al + Cu(NO3)2 Cu + Al(NO3)3Copyright2000 by Houghton Mifflin Company. All rights reserved. *AlCuCu(NO3)2Al(NO3)3Copyright2000 by Houghton Mifflin Company. All rights reserved. What is oxidizing agent in the following equation?Al + Cu(NO3)2 Cu + Al(NO3)3Copyright2000 by Houghton Mifflin Company. All rights reserved. *AlCuCu(NO3)2Al(NO3)3Copyright2000 by Houghton Mifflin Company. All rights reserved. Which substance is serving as the reducing agent in the following reaction?14H+ + Cr2O72- + 3Ni 3Ni2+ + 2Cr3+ + 7H2OCopyright2000 by Houghton Mifflin Company. All rights reserved. *H2OH+Ni2+NiCr2O72-Copyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Balancing by Half-Reaction Method1.Write separate reduction, oxidation reactions.2.For each half-reaction: Balance elements (except H, O) Balance O using H2O Balance H using H+ Balance charge using electronsCopyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Balancing by Half-Reaction Method (continued)3.If necessary, multiply by integer to equalize electron count.4.Add half-reactions.5.Check that elements and charges are balanced.Copyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Half-Reaction Method - Balancing in Base1.Balance as in acid.2.Add OH that equals H+ ions (both sides!)3.Form water by combining H+, OH.4.Check elements and charges for balance.Copyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Performing Calculations for Acid-Base Reactions1.List initial species and predict reaction.2.Write balanced net ionic reaction.3.Calculate moles of reactants.4.Determine limiting reactant.5.Calculate moles of required reactant/product.6.Convert to grams or volume, as required.Copyright2000 by Houghton Mifflin Company. All rights reserved. Copyright2000 by Houghton Mifflin Company. All rights reserved. *Key Titration Terms Titrant - solution of known concentration used in titration Analyte - substance being analyzed Equivalence point - enough titrant added to react exactly with the analyte Endpoint - the indicator changes color so you can tell the equivalence point has been reached.Copyright2000 by Houghton Mifflin Company. All rights reserved. *

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