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Solutions

Solutions. Why does a raw egg swell or shrink when placed in different solutions?. 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. Parts of a Solution.

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Solutions

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

  2. Some Definitions A solution is a HOMOGENEOUSmixture of 2 or more substances in a single phase. One constituent is usually regarded as the SOLVENTand the others as SOLUTES.

  3. 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

  4. K+(aq) + MnO4-(aq) IONIC COMPOUNDSDissolve in water! Create Aqueous Solutions KMnO4 in water

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

  6. 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!!!

  7. 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

  8. PROBLEM: Dissolve 5.00 g of NiCl2•6 H2O in enough water to make 250 mL of solution. Calculate the Molarity. Step 1: Calculate moles of NiCl2•6H2O Step 2: Calculate Molarity [NiCl2•6 H2O] = 0.0841 M

  9. USING MOLARITY What mass of oxalic acid, H2C2O4, is required to make 250. mL of a 0.0500 M solution? Step 1: Change mL to L. 250 mL * 1L/1000mL = 0.250 L Step 2: Calculate. Moles = (0.0500 mol/L) (0.250 L) = 0.0125 moles Step 3: Convert moles to grams. (0.0125 mol)(90.00 g/mol) = 1.13 g moles = M•V

  10. 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

  11. Solution M = moles of solute Liters of solution M * V = moles 3.0 mol/L * 0.400 L = 1.2 mol NaOH 1.2 mole NaOH x 40.0 g NaOH 1 mole NaOH = 48 g NaOH

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

  13. 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

  14. 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

  15. 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

  16. Dilutions • What is a volumetric flask? • Using the stock solution 2.30M NiCl2 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.

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