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2 Solutions Why does a raw egg swell or shrink when placed in different solutions?

3 Some Definitions A solution is a HOMOGENEOUS mixture of 2 or more substances in a single phase. One constituent is usually regarded as the SOLVENT and the others as SOLUTES.

4 Parts of a Solution SOLUTE – the part of a solution that is being dissolved (usually the lesser amount) SOLVENT – the part of a solution that dissolves the solute (usually the greater amount) Solute + Solvent = Solution SoluteSolventExample solid Alloys (brass, steel) solidliquidSalt water gassolidAir bubbles in ice cubes liquid “suicides” (mixed drinks) gasliquidSoft drinks gas Air

5 IONIC COMPOUNDS Dissolve in water! Create Aqueous Solutions KMnO 4 in water K + (aq) + MnO 4 - (aq)

6 Concentration of Solute The amount of solute in a solution is given by its concentration The amount of solute in a solution is given by its concentration. Molarity (M) = moles solute liters of solution

7 Think of O.J! Do you like Concentrated Orange Juice? What does that mean? What if we could describe the amount of Orange Juice in a solution. That’s why we have Molarity!!!

8 To make a 1 M solution of Copper (II) Sulfate Add 1 Mole of Copper Sulfate Add Enough water so that the SOLUTION has a volume of 1 L

9 PROBLEM: Dissolve 5.00 g of NiCl 2 6 H 2 O in enough water to make 250 mL of solution. Calculate the Molarity. Step 1: Calculate moles of NiCl 2 6H 2 O Step 2: Calculate Molarity NiCl 2 6 H 2 O [NiCl 2 6 H 2 O ] = M

10 Step 1: Change mL to L. 250 mL * 1L/1000mL = L Step 2: Calculate. Moles = ( mol/L) (0.250 L) = moles Step 3: Convert moles to grams. ( mol)(90.00 g/mol) = 1.13 g USING MOLARITY moles = MV What mass of oxalic acid, H 2 C 2 O 4, is required to make 250. mL of a M solution?

11 Learning Check How many grams of NaOH are required to prepare 400. mL of 3.0 M NaOH solution? 1)12 g 2)48 g 3) 300 g

12 Solution M = moles of solute Liters of solution M * V = moles 3.0 mol/L * L = 1.2 mol NaOH 1.2 mole NaOH x 40.0 g NaOH 1 mole NaOH = 48 g NaOH

13 Preparing Solutions Weigh out a solid solute and dissolve in a given quantity of solvent.Weigh out a solid solute and dissolve in a given quantity of solvent.

14 Mixing Solutions How would you make 500.mL of a 2.50M NaOH solution? Step 1: Convert volume mL to L. 500.mL * 1L/1000mL =.500L Step 2: Calculate number of moles NaOH needed. moles = M * liters moles = 2.50M *.500L = 1.25 moles NaOH

15 How can you “Dilute Solutions” MV=MV How would you make 100 mL of a.1 M NaOH solution from a 1 M stock solution? (.1L)(.1M/L) =1M X 1M.01 L or 10 mL and add 90 mL of water

16 Your tasks… Make 20 mL of a.100M Sucrose solution Create 30 mL of a.2 M solution from a Stock solution of 2 Molar Iodine Solution

17 What is a volumetric flask? Using the stock solution 2.30M NiCl 2 Solution make another, more dilute, solution of known concentration. From the new dilute solution make another even more dilute solution of known concentration. From the second new dilute solution make a third dilute solution of known concentration that will be the most dilute. DilutionsDilutions