Solutions and ElectrolytesLiquids, Phase Diagrams, and Phase ChangesSolutions – The BasicsConcentration: Measures of Solute AbundanceDilutions and AliquotsPractice ProblemsElectrolyte SolutionsThe Solution ProcessReview: Ionic vs. Molecular CompoundsPractice ProblemIdentifying an ElectrolyteIs an Electrolyte Strong or Weak?Common MisconceptionDemo: Electrolytes and Light BulbsPractice ProblemPractice ProblemsElectrolyte FlowchartPractice with the FlowchartWhat You Should KnowSolutions and ElectrolytesCH110 FA11 SAS 1Prepare for Recitation October 27thALEKS Objective 9 due October 25thANGEL Quiz 9, October 27thLecture 25: October 19thLecture 26: October 21stLecture 27: October 24thRead: Ch. 18.1-18.4,5.5,11.3-11.6Additional Preparation: BLB 18: 9,11,15,29,69 Packet 18: 1-3BLB 11: 31,33,37,39,43,47,50; Packet 11: 5-13CH110 FA11 SAS 2By the end of Today’s Lecture you should know:SolutionsElectrolytesKEY QUESTIONS: THE BIG PICTURELiquids, Phase Diagrams, and Phase ChangesWhat intermolecular forces are found in liquids?How do we express concentration and perform calculations for dilutions?What are electrolytes?Remember: macroscopic properties come from microscopic originsHow do IMFs influence the dissolution process?What types of compounds tend to be strong, weak, or non- electrolytes?Solutions – The BasicsCH110 FA11 SAS 3Solution:• Solutions consist of a _______ , which is typically present in the _______ amount and one or more _______ , which are dissolved and typically ____ abundant• Aqueous solutions:Solutions in the environment• Large concentrations:• Small concentrations:Concentration: Measures of Solute AbundanceCH110 FA11 SAS 4Mass Percent (%)Parts per million (ppm)Mole FractionMolarity (M)Molality (m)Dilutions and AliquotsCH110 FA11 SAS 5• Dilution changes the amount of _______present, but not the number of moles of ______ in the solution• Dilution problems are easier to solve if you remember the definition of molarity:• Aliquot :• A serial dilution is made by diluting an aliquot to a known volume.M = n/Vn = MV = constantM1V1= M2V2Practice ProblemsCH110 FA11 SAS 6What mass of sucrose (C12H22O11) is needed to make a 250 mL aqueous solution that is 0.750 M in sucrose?If a 10 mL aliquot of this solution is dilutedto 500 mL with water, what is the concentration of sucrose in the new solution?Electrolyte SolutionsCH110 FA11 SAS 7Strong electrolytes• Ionization in solution: • Good conductorsWeak electrolytes• Ionization in solution: • Poor conductorsNon-electrolytes• Ionization in solution: • Non-conductorsElectrolyte:The Solution ProcessCH110 FA11 SAS 8Dissolution of an electrolyte in water Dissolution of a non-electrolyte in water1)2)Review: Ionic vs. Molecular CompoundsCH110 FA11 SAS 9Usually composed of both metals and non-metals, but not always!K2SO4Mg(NO3)2NH4ClIonic compound:Molecular compound:Composed completely of nonmetals or nonmetals and metalloidsHClH2ONH3Practice ProblemCH110 FA11 SAS 10What is the total molar concentration of ions present in a 0.025 M aqueous solution of magnesium nitrate?A. 0.025 MB. 0.050 MC. 0.075 MD. 0.100 ME. 0.125 MIdentifying an ElectrolyteCH110 FA11 SAS 11• If a compound is _____ it is a strong electrolyte (but it might be insoluble…)• If a compound is _________ , it is an electrolyte if it is ______________Examples of electrolytesAcids donate H+(aq)Bases accept H+(aq)SaltsExamples of non-electrolytesAlcoholsCarbohydrates (sugar)Aldehydes, ketonesExamples of WEAK electrolytesWeak acids (including carboxylic acids)Weak bases (including amines)Is an Electrolyte Strong or Weak?CH110 FA11 SAS 12• Assume all salts are ______ electrolytes• You need to learn the strong acids and strong bases; all are ______ electrolytes• If a compound is an acid or a base, but it is NOT a strong acid or base, it MUST be a _____ electrolyteCommon MisconceptionCH110 FA11 SAS 13It is a common misconception that all strong electrolytes are ionic compounds. This is NOT TRUE!!!Is HCl a molecular or ionic compound?A. MolecularB. IonicIs HCl a strong or weak acid?A. StrongB. WeakIs HCl a strong or weak electrolyte?A. StrongB. WeakDemo: Electrolytes and Light BulbsCH110 FA11 SAS 14Distilled H2OTap H2ONaCl (aq)1 M HCl (aq)1M CH3COOHSugar (aq)CH3OH• For the bulb to light, some minimum amount of current is needed• Amount oc current is related to the conductivity of the solution• Conductivity (ability to conduct electricity) is related to electrolyte strengthBulb Wattage7.5 25 40Practice ProblemCH110 FA11 SAS 15Based on the results of the demo, which one of the following is a weak electrolyte?A) Distilled waterB) NaCl (aq)C) 1M HCl (aq)D) 1M CH3COOH (aq)E) Sugar (aq)F) CH3OH (aq)Practice ProblemsCH110 FA11 SAS 16Which one of the following is an ioniccompound?A. H2OB. NH4ClC. CH3COOHD. NH3Which of the following is/are a weakelectrolyte(s)?HBrNH4ClCH3CH2COOHNH3Electrolyte FlowchartCH110 FA11 SAS 17Water solublecompoundmolecular ionicstrong electrolyteIs it an acid?yes noIs it a strong acid? Is it a molecular base?yes no yes nostrong electrolyteweak electrolyteweak electrolytenon-electrolytePractice with the FlowchartCH110 FA11 SAS 18Categorize the following water soluble compounds as strong, weak, or non-electrolytes:Strong Weak Non-HClNaClCH3OHCH3COOHNH3Fe(NO3)2Ca(OH)2What You Should Know CH110 FA11 SAS 19Solutions and Dilutions• What is a homogeneous solution?• What is the difference between a solvent and a solute?• What are the commonly used units of solute concentration and how do you convert them?• How do you calculate the final concentration of a solute after a dilution?Electrolytes• What is a strong electrolyte and how do you identify one?• What is a weak electrolyte and how do you identify one?• What is a nonelectrolyte and how do you identify one?• How do you describe the dissolution process for electrolytes and
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