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Chemistry 16.2. 16.2. Molarity. A dilute solution is one that contains a small amount of solute. A concentrated solution contains a large amount of solute. 16.2. Molarity. Molarity ( M ) is the number of moles of solute dissolved in one liter of solution. 16.2. Molarity.
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16.2 Molarity • A dilute solution is one that contains a small amount of solute. • A concentratedsolution contains a large amount of solute.
16.2 Molarity • Molarity (M) is the number of moles of solute dissolved in one liter of solution.
16.2 Molarity • To make a 0.5-molar (0.5M) solution, first add 0.5 mol of solute to a 1-L volumetric flask half filled with distilled water.
16.2 Molarity • Swirl the flask carefully to dissolve the solute.
16.2 Molarity • Fill the flask with water exactly to the 1-L mark.
for Sample Problem 16.2 Problem Solving 16.8 Solve Problem 8 with the help of an interactive guided tutorial.
16.3 Sample Problem 16.3
16.3 Sample Problem 16.3
16.3 Sample Problem 16.3
16.2 Making Dilutions • Making Dilutions • What effect does dilution have on the total moles of solute in a solution?
16.2 Making Dilutions • Diluting a solution reduces the number of moles of solute per unit volume, but the total number of moles of solute in solution does not change.
16.2 Making Dilutions • The total number of moles of solute remains unchanged upon dilution, so you can write this equation. • M1 and V1 are the molarity and volume of the initial solution, and M2 and V2 are the molarity and volume of the diluted solution.
16.2 Making Dilutions • Making a Dilute Solution
16.2 Making Dilutions • To prepare 100 ml of 0.40M MgSO4 from a stock solution of 2.0M MgSO4, a student first measures 20 mL of the stock solution with a 20-mL pipet.
16.2 Making Dilutions • She then transfers the 20 mL to a 100-mL volumetric flask.
16.2 Making Dilutions • Finally she carefully adds water to the mark to make 100 mL of solution.
16.2 Making Dilutions • Volume-Measuring Devices
Bell Work: • What is the molarity of a 1500 ml solution composed of 5.3 moles of NaCl?
16.2 Percent Solutions • Percent Solutions • What are two ways to express the percent concentration of a solution?
16.2 Percent Solutions • The concentration of a solution in percent can be expressed in two ways: • ratio of the volume of the solute to the volume of the solution • ratio of the mass of the solute to the mass of the solution.
16.2 Percent Solutions • Concentration in Percent (Volume/Volume)
16.2 Percent Solutions • Isopropyl alcohol (2-propanol) is sold as a 91% solution. This solution consist of 91 mL of isopropyl alcohol mixed with enough water to make 100 mL of solution.
16.2 Percent Solutions • Concentration in Percent (Mass/Mass)
16.2 Section Quiz. • 16.2.
16.2 Section Quiz. • 1. To make a 1.00M aqueous solution of NaCl, 58.4 g of NaCl are dissolved in • 1.00 liter of water. • enough water to make 1.00 liter of solution • 1.00 kg of water. • 100 mL of water.
16.2 Section Quiz. • 2. What mass of sodium iodide (NaI) is contained in 250 mL of a 0.500M solution? • 150 g • 75.0 g • 18.7 g • 0.50 g
16.2 Section Quiz. • 3. Diluting a solution does NOT change which of the following? • concentration • volume • milliliters of solvent • moles of solute
16.2 Section Quiz. • 4. In a 2000 g solution of glucose that is labeled 5.0% (m/m), the mass of water is • 2000 g. • 100 g. • 1995 g. • 1900 g.
