Chemistry 11, Solution Chemistry, Unit 08 1 Lesson 01 And .

1Chemistry 11, Solution Chemistry, Unit 08Lesson 01 and 02: Solutions, Solubility and Conductivity01 What is a Solution?Before we can talk about solubility it is important to look at theterm solution. What is a solution?A solution is a homogeneous mixture (uniform in composition)composed of two or more substances. In such a mixture, asolute is dissolved in a solvent. A solute is the substancebeing dissolved and a solvent is the substance beingdissolved into.SoluteCommonGasLiquidLiquidOxygen and in nitrogenWater vapour in air.(air).Carbon dioxide in water.SolidSolventGasSolutionsHydrogen dissolvesrather well in metals;platinum has beenstudied as a storagemedium.Ethanol in water;varioushydrocarbons ineach other.SolidNaphthalene slowlysublimes in air.Sucrose in water;sodium chloride inwater; gold in mercury,forming an amalgam.Hexane in paraffinSteel, aluminum, otherwax, mercury inmetal alloys.gold.

Chemistry 11, Solution Chemistry, Unit 08202 What is Solubility?Solubility is generally considered to be the maximum amountof a substance (the solute) that can be dissolved into a givenamount of solvent, at a particular temperature.Once a solution has reached the limit of the solute’s andsolvent's solubility, the solution is said to be saturated,meaning that it can hold no more solute. If additional solute isadded to a saturated solution, the extra solute will settle out,forming a separate layer.

Chemistry 11, Solution Chemistry, Unit 083If a solution has not dissolved the maximum amount of aparticular substance it is said to be unsaturated.If a solution has dissolved more than the maximum amount ofa particular substance (than it would normally) it is said to besupersaturated.Saturated, Unsaturated and Supersaturated Solutions

4Chemistry 11, Solution Chemistry, Unit 0803 Distinguishing Aqueous Solutions: ConductivityThere are two main types of aqueous solutions. Each solutioncontains compounds that are held together differently. Eachsolution can be distinguished from the other based onconductivity Two Main Types of SolutionsSolutions ContainingSolutions ContainingCovalent CompoundsIonic Compoundscovalent bondingionicbondingsharing of electronstransfer of electronsgases, organic compounds,diatomic molecules CO2 , NO2 , C2H2 , CH4 ,C6H12O6 , N2 , O2 , H2 , S8 acids, bases and saltsHCl , NaOH , NaCl Covalent and Ionic CompoundsCovalent compounds are compounds composed of a nonmetal and a non-metal. Covalent compounds form molecularsolutions C2H2 (g) C2H2 (aq)CO2 (g) CO2 (aq)

Chemistry 11, Solution Chemistry, Unit 085Ionic compounds are typically composed of a metal (positivecharge) and a non-metal (negative charge), but can be nonmetal (positive charge) and non-metal (negative charge). Ioniccompounds form ionic solutions Acids: HCl(l) H (aq) Cl (aq)Bases: NaOH(s) Na (aq) OH (aq)Salts: NaCl(s) Na (aq) Cl (aq)Conductivity of Covalent and Ionic SolutionsHow can one determine whether or not a solution contains anionic substance or a covalent substance? If a solution containsions the solution will conduct electricity. If not, it will not.

Chemistry 11, Solution Chemistry, Unit 086Concentration and ConductivityKeep in mind that concentration plays a part in conductivity aswell.If a solution is ionic and the concentration is low theconductivity will also be low. If the solution is ionic andconcentration is high the conductivity will be high.If a solution is molecular, the conductivity will always be low,no matter the concentration.ExampleWhich of the following solutions are conductive and which arenot?BaBr2 (aq)CO2 (aq)KBr(s)K 2CrO4 (aq)NaNO3 (s)C6H12O6 (aq)ExampleWhich of the following pairs of solutions would you expect tobe the most conductive?1 M BaBr2 (aq)0.5 M BaBr2 (aq)0.2 M K 2CrO4 (aq)2 M K 2CrO4 (aq)1 M FeCl3 (l)1 M K 2CrO4 (aq)1 M H3PO4 (aq)1 M HNO3 (aq)

Chemistry 11, Solution Chemistry, Unit 087ExampleDescribe what you would observe if you were to test thefollowing two solutions for conductivity: (1) a solutioncontaining a small number of ions, and (2) a solutioncontaining a large number of ions.

8Chemistry 11, Solution Chemistry, Unit 08Lesson 03, 04 and 05: Intermolecular Forces andProperties of Substances01 BackgroundWhen a substance dissolves, boils, or melts the moleculesinvolved must be driven apart, and stay apartIn order to stay apart, the forces of attraction betweenmolecules must be overcome.Two question must then be answered what forces are present? how strong are they?02 Intermolecular Forces ReviewThere are two types of intermolecular forces of concern tous. permanent dipole - permanent dipole force, such as thehydrogen bond instantaneous dipole - induced dipole force such as theLondon dispersion forceOf the two types of intermolecular forces

Chemistry 11, Solution Chemistry, Unit 08 9permanent dipole - permanent dipole forces involvemolecules that are polarPolar Moleculesunequal sharing of electronsSharing of Electronsbetween bonded atomsasymmetrical arrangement ofArrangement of Atomsbonded atomsExamples ( HF and H2O )

10Chemistry 11, Solution Chemistry, Unit 08 instantaneous dipole - induced dipole force involvemolecules that are not polar but become polarNon-Polar Moleculesequal or unequal sharing ofSharing of Electronselectrons between bondedatomssymmetrical arrangement ofArrangement of Atomsbonded atomsExampleExample 01

11Chemistry 11, Solution Chemistry, Unit 08Classify Compounds as Polar or ethanolYESbenzeneNO03 Intermolecular Forces and Properties of Substance

12Chemistry 11, Solution Chemistry, Unit 08Properties of substances such as melting, boiling or dissolvingrequire that intermolecular forces be overcome. This can beeasy or difficult depending on the strength and combination ofintermolecular forces involved.Relative Strengths of Intermolecular Forces (kJ/mol)Permanent Dipole– PermanentInstantaneous Dipole – Induced DipoleDipoleAll OtherLondon DispersionHydrogen BondPD - PDForces10-405-250.05-40Example 02Boiling Points and Intermolecular ForcesExampleBoiling Number of IntermolecularBoiling

13Chemistry 11, Solution Chemistry, Unit 08ElectronsN2 (l)-196C14O2 (l)-183C16NO(l)-152C15Br2 (l)59C70ICI(l)97C70Force(s)Presentsmall Londondispersion forcesmall Londondispersion forcesmall Londondispersion forceand dipole forcelarge Londondispersion forcelarge Londondispersion forceand dipole forceExample 03Melting Points and Intermolecular ForcesIntermolecularMelting Number ofExampleForce(s)Temp.ElectronsPresentPointhigh lowTemp.MeltingPoint

14-133CAsH3-116CSbH3-88ChighPH3high low-78CLondondispersionforces andhydrogenbondingdecreasingLondonforces NH3decreasing Chemistry 11, Solution Chemistry, Unit 08Example 04Determine the Highest Boiling PointCompoundCompound 01Reasons02

15Chemistry 11, Solution Chemistry, Unit 08H2OCH3CH2OHCH3CH3H2SCompound 01, because itcontains hydrogen bonding andLondon forces.CH3CH2SHCompound 01, because itcontains hydrogen bonding andLondon forces.CH3NH2Compound 02, because itcontains hydrogen bonding andLondon forces.04 Intermolecular Forces and the Dissolving Process

Chemistry 11, Solution Chemistry, Unit 0816The dissolving process involves a consideration of the types ofintermolecular attractive forces between solute-solutemolecules and solvent-solvent molecules A solute WILL DISSOLVE in a solvent if the solutesolvent forces of attraction are great enough to

Chemistry 11, Solution Chemistry, Unit 0817overcome the solute-solute and solvent-solvent forces ofattraction. A solute WILL NOT DISSOLVE if the solute-solventforces of attraction are weaker than individual solute andsolvent intermolecular attractionsThe reason for this is because these intermolecular attractionsmust be broken before new solute-solvent attractive forcescan be established.

18Chemistry 11, Solution Chemistry, Unit 08Therefore, in general ions are attracted to the molecules of polar solvents non-polar molecules are attracted to non-polar moleculesof non-polar solventsA polar substance is more likely to dissolve in a polar solvent,and a non-polar substance is more likely to dissolve in a nonpolar solvent like dissolves likeExample 05Solubility of Polar and Nonpolar Solutesin Polar SolventsPolar SolventYESPolar SolutePermanent dipole – permanent dipole forcesand London Dispersion forces present.NONonpolarSoluteOnly London dispersion forces present.Cannot overcome dipole forces of polarsolvent.Example 06Solubility of Polar and Nonpolar Solutesin Nonpolar SolventsNonpolar SolventPolar SoluteNO

19Chemistry 11, Solution Chemistry, Unit 08Only London dispersion forces present.Cannot overcome dipole forces of polarsolute.YESNonpolarSoluteOnly London dispersion forces present. Nodipole forces to overcome.Example 07Classify as Soluble or olute / SolventSodium NitrateExample 08Classify as Soluble or InsolubleSolute / SolventWaterCarbonTetrachloride

20Chemistry 11, Solution Chemistry, Unit 08Carbon disulphideInsolubleSolubleExample 09Classify as Soluble or eSolute / SolventFormaldehydeExample 10Classify as Soluble or InsolubleCarbonSolute / SolventAcetoneTetrachloride

21Chemistry 11, Solution Chemistry, Unit 08SulphurSolubleInsoluble05 Aqueous Solutions: The Dissolving ProcessThe dissolving process, sometimes called solvation ordissolution, is the process of attraction and association ofmolecules of a solvent with molecules or ions of a solute. Ifsolute and solvent intermolecular forces are compatible, solutemolecules or ions dissolve, spread out, and becomesurrounded by solvent molecules.

Chemistry 11, Solution Chemistry, Unit 0822Two terms that describe the formation of ions in solution, andare often confused are. dissociation: Refers to the formation of ions from an ionicsolid. Remember an ionic solid is composed of a metaland a nonmetal. Ions already exist in an ionic solid. Allthat is happening is separation of those ions.NaCl(s) Na (aq) Cl (aq)

23Chemistry 11, Solution Chemistry, Unit 08 ionization: Refers to the formation of ions from a covalentor molecular solid. Ions do not exist until the solvent hasreacted.CH3COOH(l) CH3COO- (aq) H (aq)Example 11Write Dissociation / Ionization EquationsCompoundEquationCa OH 2 (s)Ca OH 2 (s) Ca2 (aq) 2OH- (aq)HCl(g)HCl(g) H (aq) Cl (aq) NH4 2 S(s) NH4 2 S(s) 2NH4 (aq) S2- (aq)AlCl3 (s)AlCl3 (s) Al3 (aq) 3Cl- (aq)

24Chemistry 11, Solution Chemistry, Unit 08Lesson 06: Concentration of Ions in Aqueous Solutions01 Ion Concentrations for Solids Added to WaterWhen determining ion concentrations for solutions it isimportant to remember the mole ratio concept for balancedchemical reactions. determine the balanced chemical reaction fordissociation concentrations of ions present depends on the mole ratiobetween reactants and productsExample 01Calculate the concentrations of each ion for the followingsolution 12.0 grams of NH4 2 CO3 in 2.50 liters of water first write out the dissociation reaction NH4 2 CO3 (aq) 2NH4 (aq) CO32 (aq) second, calculate the concentration of the substance inwater before dissociation takes place 12.0 g NH4 2 CO3 1 mole NH4 2 CO3 2.50 L 96.0 g NH4 2 CO3 0.0500 M NH4 2 CO3 lastly, calculate the concentration of all ions

Chemistry 11, Solution Chemistry, Unit 0825 NH4 2 0.0500 M NH4 CO3 0.100 M2 CO32 1 0.0500 M NH4 CO3 0.0500 M2 02 Ion Concentrations for DilutionsFor convenience, solutions are either purchased or preparedin concentrated stock solutions which must be diluted prior touse.When we take a sample of a stock solution we have a certainconcentration of molecules in that sample.Dilution alters the concentration of the solution but not the total number of moles in the solution.