**SolutionsChapter 12 Modern Chemistry** Sections 1-3 Types of Mixtures The Solution Process Concentrations of Solution Chapter 12 Section 3 Concentration of Solutions p. 418-424

**Section 12.3** Concentration of Solutions Chapter 12 Section 3 Concentration of Solns p. 418-424

**Vocabulary** Concentration Concentrated Dilute Molarity Molality Dilution Chapter 12 Section 3 Concentration of Solns p. 418-424

**Concept Map 12.3** CONCENTRATED DILUTE MOLARITY CONCENTRATION MOLALITY DILUTIONS Chapter 12 Section 3 Concentration of Solns p. 418-424

**Concentration** • Concentration is a measure of the amount of solute in a given amount of solvent or solution. • Dilute means that there is a small amount of solute. • Concentration means that there is a large amount of solute. • There are many ways to quantify concentration. Chapter 12 Section 3 Concentration of Solns p. 418-424

**Concentration Units** Chapter 12 Section 3 Concentration of Solns p. 418-424

**Concentration & Molarity** p. xx Chapter 12 Section 3 Concentration of Solns p. 418-424

**mol** M = L Molarity The number of moles of solute in one liter of solution. moles of solute M = liters of solution Chapter 12 Section 3 Concentration of Solns p. 418-424

**Making a Molar Solution** p. 419 Chapter 12 Section 3 Concentration of Solns p. 418-424

**Making a Molar Solution** p. xx Insert Holt Disc 2 Chapter 12 Section 3 Concentration of Solns p. 418-424

**Molarity Sample Problems** 1.0.440 M NaCl • You have 3.50 L of solution that contains 90.0 g of sodium chloride, NaCl. What is the molarity of that solution? • You have 0.8 L of a 0.5 M HCl solution. How many moles of HCl does this solution contain? • To produce 40.0 g of silver chromate, you will need at least 23.4 g of potassium chromate in solution as a reactant. All you have on hand is 5 L of a 6.0 M K2CrO4 solution. What volume of the solution is needed to give you the 23.4 g K2CrO4 needed for the reaction? p. 420-421 2. 0.4 mol HCl 3. 0.020 L K2CrO4 Chapter 12 Section 3 Concentration of Solns p. 418-424

**Molarity Practice Problems** • What is the molarity of a solution composed of 5.85 g of potassium iodide, KI, dissolved in enough water to make 0.125 L of solution? • How many moles of H2SO4 are present in 0.500 L of a 0.150 M H2SO4 solution? • What volume of 3.00 M NaCl is needed for a reaction that requires 146.3 g of NaCl? 1.0.282 M KI p. 421 2. 0.0750 mol 3. 0.834 L Chapter 12 Section 3 Concentration of Solns p. 418-424

**Molarity vs. Molality** p. xx Chapter 12 Section 3 Concentration of Solns p. 418-424

**mol** m = Kg Molality The number of moles of solute per kilogram of solvent. moles of solute m = kilograms of solvent The density of water is 1 g / mL. So, 1 g = 1 mL and 1kg = 1 L Chapter 12 Section 3 Concentration of Solns p. 418-424

**Making a Molal Solution** p. 422 Chapter 12 Section 3 Concentration of Solns p. 418-424

**Molality Sample Problems** • A solution was prepared by dissolving 17.1 g of sucrose (table sugar, C12H22O11) in 125 g of water. Find the molal concentration of this solution. • A solution of iodine, I2, in carbon tetrachloride, CCl4, is used when iodine is needed for certain chemical tests. How much iodine must be added to prepare a 0.480 m solution of iodine in CCl4 if 100.0 g of CCl4 is used? 1.0.400 m C12H22O11 p. 423-424 2. 12.2 g I2 Chapter 12 Section 3 Concentration of Solns p. 418-424

**Molality Practice Problems** • What is the molality of acetone in a solution composed of 255 g of acetone, (CH3)2CO, dissolved in 200. g of water? • What quantity, in grams, of methanol, CH3OH, is required to prepare a 0.244 m solution in 400. g of water? 1.22.0 m acetone p. 424 2. 3.13 g CH3OH Chapter 12 Section 3 Concentration of Solns p. 418-424

**Volume of New Solution Wanted** Original Molarity Volume of Original Solution Needed NewMolarity Diluting a Solution How much of an original solution is needed to make a less concentrated solution by adding water? M1 V1 = M2 V2 Chapter 12 Section 3 Concentration of Solns p. 418-424

**Diluting a Solution** p. xx Insert Holt Disc 2 Chapter 12 Section 3 Concentration of Solns p. 418-424

**Dilution Problems** P. 902 # 367. What is the molarity of a solution of ammonium chloride prepared by diluting 50.00 mL of a 3.79 M NH4Cl solution to 2.00 L? P. 903 #370. To what volume should 1.19 mL of an 8.00 M acetic acid solution be diluted in order to obtain a final solution that is 1.50 M? 0.0948 M 6.35 mL Chapter 12 Section 3 Concentration of Solns p. 418-424

**Dilution Problems** P. 903 # 371. What volume of a 5.75 M formic acid solution should be used to prepare 2.00 L of a 1.00 M formic acid solution? P. 903 #372. A 25.00 mL sample of ammonium nitrate solution produces a 0.186 M solution when diluted with 50.00 mL of water. What is the molarity of the stock solution? 348 mL 0.558 M Chapter 12 Section 3 Concentration of Solns p. 418-424

**Ch 12 Sec 3 Homework** Molarity, Molality, Dilution Problem Bank Page 902-903 #345-347, 350-352, 375 Chapter 12 Section 3 Concentration of Solns p. 418-424