Reactions in Aqueous Solution Chapter 4 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

4.1 A ______________ is a homogenous mixture of 2 or more substances The ___________ is(are) the substance(s) present in the smaller amount(s) The ____________ is the substance present in the larger amount SolutionSolventSolute Soft drink (l) Air (g) Soft Solder (s) H2OH2O N2N2 Pb Sugar, CO 2 O 2, Ar, CH 4 Sn

An __________ is a substance that, when dissolved in water, results in a solution that can conduct electricity. A ______________ is a substance that, when dissolved, results in a solution that does not conduct electricity. nonelectrolyte weak electrolyte strong electrolyte 4.1

__________ Electrolyte – 100% dissociation NaCl (s) Na + (aq) + Cl - (aq) H2OH2O __________ Electrolyte – not completely dissociated CH 3 COOH CH 3 COO - (aq) + H + (aq) Conduct electricity in aqueous solution? Cations (+) and Anions (-) 4.1

_________________ of acetic acid CH 3 COOH CH 3 COO - (aq) + H + (aq) 4.1 A _______________ reaction. The reaction can occur in both directions. Acetic acid is a __________ ________________ because its ionization in water is incomplete.

__________ is the process in which an ion is surrounded by water molecules arranged in a specific manner.   H2OH2O 4.1

________________ does not conduct electricity? No cations (+) and anions (-) in solution 4.1 C 6 H 12 O 6 (s) C 6 H 12 O 6 (aq) H2OH2O

Precipitation Reactions ___________ – insoluble solid that separates from solution __________ equation __________ __________ equation Pb NO Na + + 2I - PbI 2 (s) + 2Na + + 2NO 3 - Na + and NO 3 - are __________ ions PbI 2 Pb(NO 3 ) 2 (aq) + 2NaI (aq) PbI 2 (s) + 2NaNO 3 (aq) precipitate Pb I - PbI 2 (s) 4.2

Precipitation of Lead Iodide PbI 2 Pb I - PbI 2 (s) 4.2

_________ is the maximum amount of solute that will dissolve in a given quantity of solvent at a specific temperature.

Writing Net Ionic Equations 1.Write the balanced molecular equation. 2.Write the ionic equation showing the strong electrolytes completely dissociated into cations and anions. 3.Cancel the spectator ions on both sides of the ionic equation 4.Check that charges and number of atoms are balanced in the net ionic equation AgNO 3 (aq) + NaCl (aq) AgCl (s) + NaNO 3 (aq) Ag + + NO Na + + Cl - AgCl (s) + Na + + NO 3 - Ag + + Cl - AgCl (s) 4.2 Write the net ionic equation for the reaction of silver nitrate with sodium chloride.

Chemistry In Action: CO 2 (aq) CO 2 (g) Ca 2+ (aq) + 2HCO 3 (aq) CaCO 3 (s) + CO 2 (aq) + H 2 O (l) - An Undesirable Precipitation Reaction 4.2

Acids Have a ________ taste. Vinegar owes its taste to _________ acid. Citrus fruits contain citric acid. React with certain metals to produce hydrogen gas. React with carbonates and bicarbonates to produce carbon dioxide gas 4.3 Cause color changes in plant dyes. 2HCl (aq) + Mg (s) MgCl 2 (aq) + H 2 (g) 2HCl (aq) + CaCO 3 (s) CaCl 2 (aq) + CO 2 (g) + H 2 O (l) Aqueous acid solutions conduct electricity.

Have a __________ taste. Feel __________. Many soaps contain bases. Bases 4.3 Cause color changes in plant dyes. Aqueous base solutions conduct electricity.

Arrhenius acid is a substance that produces H + (H 3 O + ) in water Arrhenius base is a substance that produces OH - in water 4.3

_________________ ion, hydrated proton, H 3 O + 4.3

A Brønsted __________ is a proton donor A Brønsted __________ is a proton acceptor acidbaseacidbase 4.3 A Brønsted acid must contain at least one ionizable __________ !

_______________ acids HCl H + + Cl - HNO 3 H + + NO 3 - CH 3 COOH H + + CH 3 COO - Strong electrolyte, strong acid Weak electrolyte, weak acid _______________ acids H 2 SO 4 H + + HSO 4 - HSO 4 - H + + SO 4 2- Strong electrolyte, strong acid Weak electrolyte, weak acid _______________ acids H 3 PO 4 H + + H 2 PO 4 - H 2 PO 4 - H + + HPO 4 2- HPO 4 2- H + + PO 4 3- Weak electrolyte, weak acid 4.3

Identify each of the following species as a Brønsted acid, base, or both. (a) HI, (b) CH 3 COO -, (c) H 2 PO 4 - HI (aq) H + (aq) + I - (aq)_______________ CH 3 COO - (aq) + H + (aq) CH 3 COOH (aq)_______________ H 2 PO 4 - (aq) H + (aq) + HPO 4 2- (aq) H 2 PO 4 - (aq) + H + (aq) H 3 PO 4 (aq) _______________ 4.3

Neutralization Reaction _______ + _______ HCl (aq) + NaOH (aq) NaCl (aq) + H 2 O H + + Cl - + Na + + OH - Na + + Cl - + H 2 O H + + OH - H 2 O 4.3

Oxidation-Reduction Reactions ( ______________ transfer reactions) 2Mg 2Mg e - O 2 + 4e - 2O 2- _________ half-reaction (lose e - ) _________ half-reaction (gain e - ) 2Mg + O 2 + 4e - 2Mg O e - 2Mg + O 2 2MgO 4.4

Zn (s) + CuSO 4 (aq) ZnSO 4 (aq) + Cu (s) Zn is oxidizedZn Zn e - Cu 2+ is reducedCu e - Cu Zn is the ________ agent Cu 2+ is the _______ agent 4.4 Copper wire reacts with silver nitrate to form silver metal. What is the oxidizing agent in the reaction? Cu (s) + 2AgNO 3 (aq) Cu(NO 3 ) 2 (aq) + 2Ag (s) Cu Cu e - Ag + + 1e - AgAg + is _______Ag + is the _______ agent

Oxidation number The charge the atom would have in a molecule (or an ionic compound) if electrons were completely transferred. 1.Free elements (uncombined state) have an oxidation number of zero. Na, Be, K, Pb, H 2, O 2, P 4 = 0 2.In monatomic ions, the oxidation number is equal to the charge on the ion. Li +, Li = +1; Fe 3+, Fe = +3; O 2-, O = -2 3.The oxidation number of oxygen is usually –2. In H 2 O 2 and O 2 2- it is –1. 4.4

4.The oxidation number of hydrogen is +1 except when it is bonded to metals in binary compounds. In these cases, its oxidation number is –1. 6. The sum of the oxidation numbers of all the atoms in a molecule or ion is equal to the charge on the molecule or ion. 5.Group IA metals are +1, IIA metals are +2 and fluorine is always –1. HCO 3 - O = __H = __ 3x(-2) ? = __ C = __ Oxidation numbers of all the elements in HCO 3 - ? Oxidation numbers do not have to be integers. Oxidation number of oxygen in the superoxide ion, O 2 -, is -½.

The oxidation numbers of elements in their compounds 4.4

NaIO 3 Na = __ O = __ 3x(-2) ? = __ I = __ IF 7 F = __ 7x(-1) + ? = __ I = __ K 2 Cr 2 O 7 O = __ K = __ 7x(-2) + 2x(+1) + 2x(?) = __ Cr = __ Oxidation numbers of all the elements in the following ? 4.4

Types of Oxidation-Reduction Reactions __________ Reaction A + B C 2Al + 3Br 2 2AlBr 3 __________ Reaction 2KClO 3 2KCl + 3O 2 C A + B

Types of Oxidation-Reduction Reactions __________ Reaction A + O 2 B S + O 2 SO Mg + O 2 2MgO

__________ Reaction A + BC AC + B Sr + 2H 2 O Sr(OH) 2 + H 2 TiCl 4 + 2Mg Ti + 2MgCl 2 Cl 2 + 2KBr 2KCl + Br 2 Hydrogen Displacement Metal Displacement Halogen Displacement Types of Oxidation-Reduction Reactions

The Activity Series for Metals M + BC AC + B Hydrogen Displacement Reaction M is metal BC is acid or H 2 O B is H 2 Ca + 2H 2 O Ca(OH) 2 + H 2 Pb + 2H 2 O Pb(OH) 2 + H 2 4.4

The Activity Series for Halogens Halogen Displacement Reaction 4.4 Cl 2 + 2KBr 2KCl + Br F 2 > Cl 2 > Br 2 > I 2 I 2 + 2KBr 2KI + Br 2

_________________ Reaction Cl 2 + 2OH - ClO - + Cl - + H 2 O Element is simultaneously oxidized and reduced. Types of Oxidation-Reduction Reactions Chlorine Chemistry

Ca 2+ + CO 3 2- CaCO 3 NH 3 + H + NH 4 + Zn + 2HCl ZnCl 2 + H 2 Ca + F 2 CaF 2 __________ _______ (H 2 Displacement) __________ (Combination) Classify the following reactions. 4.4

Chemistry in Action: Breath Analyzer 4.4 3CH 3 COOH + 2Cr 2 (SO 4 ) 3 + 2K 2 SO H 2 O 3CH 3 CH 2 OH + 2K 2 Cr 2 O 7 + 8H 2 SO

Solution Stoichiometry The ________________ of a solution is the amount of solute present in a given quantity of solvent or solution. M = molarity = What mass of KI is required to make 500. mL of a 2.80 M KI solution? volume of KI solutionmoles KIgrams KI M KI 500. mL= _____ g KI 166 g KI 1 mol KI x 2.80 mol KI 1 L soln x 1 L 1000 mL x 4.5

________________ is the procedure for preparing a less concentrated solution from a more concentrated solution. Dilution Add Solvent Moles of solute before dilution (i) Moles of solute after dilution (f) = MiViMiVi MfVfMfVf = 4.5

How would you prepare 60.0 mL of M HNO 3 from a stock solution of 4.00 M HNO 3 ? M i V i = M f V f M i = 4.00 M f = 0.200V f = 0.06 L V i = ? L 4.5 V i = MfVfMfVf MiMi = x = ______ L = __ mL _ mL of acid + __ mL of water= __ mL of solution

Gravimetric Analysis Dissolve unknown substance in water 2.React unknown with known substance to form a precipitate 3.Filter and dry precipitate 4.Weigh precipitate 5.Use chemical formula and mass of precipitate to determine amount of unknown ion

Titrations In a ___________ a solution of accurately known concentration is added gradually added to another solution of unknown concentration until the chemical reaction between the two solutions is complete. ___________ _____ – the point at which the reaction is complete ___________ – substance that changes color at (or near) the equivalence point Slowly add base to unknown acid UNTIL the indicator changes color 4.7

What volume of a M NaOH solution is Required to titrate mL of a 4.50 M H 2 SO 4 solution? 4.7 WRITE THE CHEMICAL EQUATION! volume acidmoles acidmoles basevolume base H 2 SO 4 + 2NaOH 2H 2 O + Na 2 SO mol H 2 SO mL soln x 2 mol NaOH 1 mol H 2 SO 4 x 1000 ml soln mol NaOH x mL = ____ mL M acid rx coef. M base

Chemistry in Action: Metals from the Sea CaCO 3 (s) CaO (s) + CO 2 (g) Mg(OH) 2 (s) + 2HCl (aq) MgCl 2 (aq) + 2H 2 O (l) CaO (s) + H 2 O (l) Ca 2+ (aq) + 2OH (aq) - Mg 2+ (aq) + 2OH (aq) Mg(OH) 2 (s) - Mg e - Mg 2Cl - Cl 2 + 2e - MgCl 2 (aq) Mg (s) + Cl 2 (g)