CHEM 1061 1st Edition Lecture 6Outline of Last Lecture I. Continuation of Empirical FormulaII. Molar Mass of a CompoundIII. Writing and Balancing Chemical EquationsIV. Limiting ReactantsOutline of Current Lecture V. Percentage YieldsVI. Solution Stoichiometrya. Diluting a Solutionb. Solubilityc. Ionic Compound in a solutiond. Moles of Ions in a Solutione. Covalent Compounds in WaterVII. Writing Equations for Aqueous Ionic CompoundsCurrent LectureI. Percentage Yieldsa. Useful in Labs but not covering in lecture.b. Page 123 in textbook, sample problem 3.21II. Solution Stoichiometrya. Aqueous solutions are those that dissolve in WATER.b. Solute: substance that is dissolved; smaller quantityc. Solvent: what dissolves the solute; larger quantity; is often waterd. Concentration is written in units called Molarity (M)e. Molarity: Moles of a solute/ L of solution = mol solute/ L solnThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.f. SAMPLE PROBLEM: What is the molarity of 500 mL of soln containing 21.2g KI? (Molar mass of KI is approx: 166g/mol)Answer: 0.255 Mg. Diluting a Solution i. Only use if you have the SAME solutionii. NOT if you are reacting two different solutions.iii. M1V1=M2V2Concentrated/initial=Dilutediv. Sample Problem 4.6h. Solubilityi. Dissolving substances in water.ii. EXAMPLE: NaCl is soluble in water.NaCl(s) –H20-> Na^+(aq) + Cl^-(aq)iii. Water is POLAR (unequal sharing of electrons) so the H are partially positive, and the O are partially negative.iv. EXAMPLE: AgCl(s) is insoluble in water.AgCl(s) –H2O->AgCl(s)v. Ionic bonds of AgCl are stronger than those of NaCl therefore they do not dissolve.i. Ionic Compound in a Solutioni. Soluble: Ionic compounds are strong ELECTROLYTESii. Electrolytes: substances that conduct a current when dissolved in wateriii. you NEED ions to conduct a currentj. Moles of Ions in Solutioni. How many moles of ions are released when 2.0 mol MgCl2 are dissolved in water?MgCl2 –H2O-> Mg^2+(aq) + 2Cl^-(aq)2.0mol MgCl2 x (1 mol Mg^2+/ 1 mol MgCl2) = 2.0 mol Mg^2+2 mol MgCl2 x (2 mol Cl^-/1 mol MgCl2) = 4.0 mol Cl^-ANSWER: 6.0 mol total ionsk. Covalent Compounds in Wateri. Substances can dissolve in H2O without separating into Ions.ii. SucroseC12H22O14(s) –H2O-> C12H22O14(aq)iii. These are called NONELECTROLYTES (does not conduct electrical current when dissolved in water.III. Writing Equations for Aqueous Ionic Compoundsa. Three Reaction Typesi. Precipitationii. Acid Baseiii. Oxidation Redution (Redox)b. Equationsi. Molecularii. Total Ioniciii. Net Ionicc. Precipitationi. Forming a solid insoluble compound from soln. (aka precipitate)ii. Example: Pb(NO3) (aq) + KI (aq) 1. Double displacement (metathesis reaction)2. AB+CD
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