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Chapter 1

Chapter 1. Properties of Solutions. Table of Contents. Introduction Nature of Solutions Solubility Mixing Aqueous Solutions Hydrolysis. Properties of Solutions. Chapter 1. Warm Up. Make a list of mixtures. Separate your list into homogeneous and heterogeneous.

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Chapter 1

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  1. Chapter 1 Properties of Solutions Table of Contents Introduction Nature of Solutions Solubility Mixing Aqueous Solutions Hydrolysis

  2. Properties of Solutions Chapter 1 Warm Up • Make a list of mixtures. • Separate your list into homogeneous and heterogeneous. • What are the mixtures that we use in life?

  3. Introduction Chapter 1 • There are many kinds of mixtures, solid, liquid or gas according to physical state as well as electrolyte or non electrolyte according to electrical conductivity. • Mixtures can be either homogeneous or heterogeneous according to structure. • They are affected from temperature and pressure.

  4. 1. Nature of Solutions Chapter 1 • Mixtures can be either homogeneous or heterogeneous. • The particles of a heterogeneous mixture are large enough to see under a microscope. Oil in water, sand in water, soup, milk, blood, soil…etc. • In a homogeneous mixture, however, the particles are molecule-sized, so the mixture appears uniform, even under a microscope. Salty water, cola, copper sulfate solution, steel, coins, fog…etc. • A solution is a homogeneous mixture of two or more substances uniformly dispersed throughout a single phase.

  5. 1. Nature of Solutions Chapter 1

  6. 1. Nature of Solutions Chapter 1 • Solution = Solvent + Solute(s) • Solvent is the component of solution in the largest amount • or that determines the state of solution. • Solute is the part of solution dissolved in a solvent. • Solutions in which water is the solvent are called aqueoussolutions. Example 1 Find the solute and solvent components of the following solutions. a. Air b. sea water c. bronze d. Vinegar

  7. 1. Nature of Solutions Chapter 1 An alloy is a homogeneous solution of two or more elements, at least one of which is a metal. For example, steel, coins, bronze, brass, solder, amalgam…etc.

  8. 1. Nature of Solutions Chapter 1 • The Dissolution Process • Dissolution is the mixing of a solute in a solvent.

  9. 1. Nature of Solutions Chapter 1 • Heat Change in Dissolution Process • Dissolution process can be either exothermic or endothermic process with respect to nature of solution. For example; • dissolution of NaCH3COO in water is exothermic process, increases the temperature to 54oC. (Heat Pack) • but dissolution of NH4NO3 is endothermic, decreases the temperature to 5oC. (Cold Pack)

  10. 1. Nature of Solutions Chapter 1 • Conductivity of Solutions • Solutions that conduct electricity are called electrolytes. Salt, acid or base solutions are electrolytes. • Strength of conductivity depends upon the ionization of solute. • If it ionizes completely it is called strong electrolyte. • If the ionization is poor, it is called weak electrolyte. • Solutions that cannot conduct electricity are called non electrolyte.

  11. 1. Nature of Solutions Chapter 1 Conductivity of Solutions

  12. 1. Nature of Solutions Chapter 1 • Change in Freezing and Boiling Points • Solutions boil at higher temperature and freeze at lower temperatures than pure liquids. Meaning more solute in a solution decreases the freezing point and increases the boiling point of solvent. • Salt is scattered on roads to prevent the freezing, or antifreeze is added to radiators in cars to prevent both freezing and boiling of water.

  13. 1. Nature of Solutions Chapter 1 • Dilute and Concentrated Solutions • Solutions that contain relatively large amount of solute are called concentrated, and relatively small amount of solute are called dilute. • Dilution is simply adding water to more concentrated solution to make it dilute. Dilute solutions Concentrated solutions

  14. 2. Solubility Chapter 1 • The solubility of a compound is the maximum amount of solute dissolved in a given amount of solvent to form a saturated solution at a particular temperature. • When a solution contains as much solute as it can dissolve, it is saturated. When it contains less solute than it can dissolve it is called unsaturated. • If the maximum amount of solute dissolved in 100 g water is less than 0.1 g this solute is accepted as insoluble. • The solute that has a solubility range 0.1 g to 1 g it is called slightly soluble. • If the amount of solute is more than 1 g then it is soluble.

  15. 2. Solubility Chapter 1 Example 2 The solubility of NaCl is 38g/100 water at 20oC. How many gram of saturated solution can be prepared by mixing 95 g NaCl with enough water at 20oC. Solution 100 g water is used for 38 g NaCl X g 95 g

  16. 2. Solubility Chapter 1 Example 3 The solubility of KNO3 is 30g/100 water at 20oC. How many gram of water must be used to prepared a saturated solution containing 120 g KNO3 at 20oC. Solution 100 g water is used for 30 g KNO3 X g 120 g

  17. 2. Solubility Chapter 1 Factors Affecting Solubility • 1. Temperature • The solubility of solids usually increase as the temperature rises. There are some exceptions to this rule; Ce2(SO4)3. • The solubility of gases decrease as the temperature rises. • 2. Pressure • The solubility of gases in liquids increase as the pressure above the liquid is increased.

  18. 2. Solubility Chapter 1 Factors Affecting Solubility

  19. 2. Solubility Chapter 1 Factors Affecting Solubility Example 4 When 40 g of NaCl is added in 60 g water, 4 g NaCl remains undissolved. What is the solubility of NaCl in 100 g water at the same temperature? Solution

  20. 2. Solubility Chapter 1 Factors Affecting Solubility • Example 5 • Solubility of a salt X is 20 g / 100g water at room temperature. 100 g of water is added into 360 g saturated solution of the salt X . How many grams of the salt X must be added to make the new solution saturated? Solution

  21. 2. Solubility Chapter 1 Factors Affecting Solubility • Example 6 • The solubility of KNO3 at 60 oC is 110 g/100 g water. 220 g of KNO3 is dissolved in 250 g of water at 60oC. How many grams of water should be evaporated from the solution to make the solution saturated? Solution

  22. 2. Solubility Chapter 1 Factors Affecting Solubility • Example 7 • A saturated solution of the salt X is prepared with 75 g of water at 10 0C . If 30 g of the salt is added and the temperature is increased to 40 0C, how many g salt x precipitates? Solution

  23. 2. Solubility Chapter 1 Factors Affecting Solubility Solution

  24. Chapter 1 3. Mixing Aqueous Solutions • Precipitation is the formation of a solid in a solution during a chemical reaction. Pb(NO3)2 (aq) + 2KI(aq)  PbI2 (s) + 2KNO3 (aq) yellow ppt • An equation that includes only the actual participants in a reaction is called net ionic equation. Pb+2(aq) + 2I-(aq)  PbI2 (s)

  25. Chapter 1 3. Mixing Aqueous Solutions HgCl2 (aq) + 2KI(aq)  HgI2 (s) + 2KCl(aq)

  26. Chapter 1 3. Mixing Aqueous Solutions Pb(NO3)2 (aq) + 2KI(aq)  PbI2 (s) + 2KNO3 (aq)

  27. Chapter 1 3. Mixing Aqueous Solutions AgNO3(aq) + NaOH(aq)  AgOH(s) + NaNO3(aq)

  28. Chapter 1 4. Hydrolysis • Interaction of an ion with water is called hydrolysis. • The salts of strong acids and strong bases do not hydrolyze, and form neutral solutions. (Na+, Cl-, K+, NO3-, SO4-2, Br-,…etc.) • The salts of weak bases and strong acids hydrolyze, and form acidic solutions. (NH4Cl, ZnBr2, CuNO3, …etc) • The salts of strong bases and weak acids hydrolyze, and form basic solutions. (NaF, KCH3COO, Li3PO4 …etc)

  29. Chapter 1 4. Hydrolysis • Example 8 • Predict whether the solutions of following salts are acidic, basic or neutral. • a.KClb. Fe(NO3)2c. Na2CO3d.LiF Solution • a.Neutralb.Acidicc.Basicd.Neutral

  30. End of the chapter 1

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