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V. Physical Behavior of Matter – B

V. Physical Behavior of Matter – B. A solution is a homogeneous mixture of a solute dissolved in a solvent. The solubility of a solute in a given amount of solvent is dependent on the temperature, the pressure, and the chemical natures of the solute and solvent. (3.1oo).

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V. Physical Behavior of Matter – B

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  1. V. Physical Behavior of Matter – B

  2. A solution is a homogeneous mixture of a solute dissolved in a solvent. The solubility of a solute in a given amount of solvent is dependent on the temperature, the pressure, and the chemical natures of the solute and solvent. (3.1oo) Dissolved particles are too small to be trapped by a filter

  3. Solubility of a nonvolatile solute depends on temperature. • Solubility is the maximum amount of solute that a solvent can hold at a given temperature. • An unsaturated solution is one in which the solvent can dissolve more solute • A saturated solution is one in which the solvent has as much solute as it can hold • A supersaturated solution is one in which there is more solute dissolved than a solvent can normally hold. • Make a supersaturated solution by cooling a saturated solution • Supersaturated solutions are unstable and will precipitate the excess solute when a seed crystal is added. • As temperature increases, solubility of a solid increases.

  4. Table G shows the solubilities of some gases and some solids at various temperatures when dissolved in 100 grams of water.

  5. A solution which is on the line is saturated • A solution below the line is unsaturated • A solution above the line is supersaturated

  6. Add a test crystal to see if a solution is unsaturated, saturated or supersaturated. • Unsaturated – the test crystal dissolves • Saturated – the test crystal settles to the bottom • Supersaturated – a large amount of crystals precipitate from the solution

  7. Regents Question: 06/02 #40 According to Reference Table G, which solution is saturated at 30°C? (1) 12 grams of KClO3 in 100 grams of water (2) 12 grams of KClO3 in 200 grams of water (3) 30 grams of NaCl in 100 grams of water (4) 30 grams of NaCl in 200 grams of water þ

  8. The solubility of a gas depends on temperature and pressure. • As temperature increases, the solubility of a gas decreases • As pressure increases, the solubility of a gas increases

  9. Which are gases?

  10. Regents Question: 08/02 #48 One hundred grams of water is saturated with NH4Cl at 50°C. According to Table G, if the temperature is lowered to 10°C, what is the total amount of NH4Cl that will precipitate? (1) 5.0 g (3) 30. g (2) 17 g (4) 50. g þ

  11. Regents Question: 01/03 #65-66 When cola, a type of soda pop, is manufactured, CO2 (g) is dissolved in it. A capped bottle of cola contains CO2 (g) under high pressure. When the cap is removed, how does pressure affect the solubility of the dissolved CO2 (g)? A glass of cold cola is left to stand 5 minutes at room temperature. How does temperature affect the solubility of the CO2 (g)? As the pressure decreases, the solubility decreases. As the temperature increases, the solubility decreases.

  12. Oil and water are not miscible • Like dissolves like (charged solutes dissolve in charged solvents, uncharged solutes dissolve in uncharged solvents) • Nonpolar solutes dissolve in nonpolar solvents • Polar solutes dissolve in polar solvents • Ionic solutes dissolve in polar solvents (Nonpolar) (Polar) Dry cleaners use a nonpolar solvent to get rid of oil and grease Liquids that dissolve each other are called miscible liquids.

  13. Regents Question: 06/03 #42 Hexane (C 6 H 14 ) and water do not form a solution. Which statement explains this phenomenon? (1) Hexane is polar and water is nonpolar. (2) Hexane is ionic and water is polar. (3) Hexane is nonpolar and water is polar. (4) Hexane is nonpolar and water is ionic. þ

  14. Solubility Guidelines • Not all substances are soluble in water • Reference Table F lists solubility rules and exceptions to those rules.

  15. Soluble Not Soluble

  16. Regents Question: 08/02 #40 Which of the following compounds is least soluble in water? (1) copper (II) chloride (2) aluminum acetate (3) iron (III) hydroxide (4) potassium sulfate þ

  17. Regents Question: 06/03 #14 • According to Table F, which of these salts is least soluble in water? • LiCl • (2) RbCl • (3) FeCl2 • (4) PbCl2 þ

  18. The concentration of a solution may be expressed as molarity (M), percent by volume, percent by mass, or parts per million (ppm). (3.1pp)

  19. Moles Molarity = Liters Regents Question: 06/02 #42 What is the molarity of a solution that contains 0.50 mole of NaOH in 0.50 liter of solution? (1) 1.0 M (3) 0.25 M (2) 2.0 M (4) 0.50 M þ

  20. Regents Question: 08/02 #36 How many moles of solute are contained in 200 milliliters of a 1 M solution? (1) 1 (3) 0.8 (2) 0.2 (4) 200 þ

  21. Molarity = moles liters Na 1 x 23.0 = 23.0 I 1 x 126.9 = 126.9 149.9 g / mole 0.010M = x 1.0 L Regents Question: 08/02 #49 What is the total number of grams of NaI(s) needed to make 1.0 liter of a 0.010 M solution? (1) 0.015 (3) 1.5 (2) 0.15 (4) 15 þ X = 0.010 moles 0.010 moles x 149.9 g/mole =

  22. Regents Question: 01/03 #40 Solubility data for four different salts in water at 60°C are shown in the table below. Which salt is most soluble at 60°C? (1) A (2) B (3) C (4) D Salt Solubility in Water at 60 °C A - 10 grams /50 grams H2O B - 20 grams /60 grams H2O C - 30 grams /120 grams H2O D - 40 grams/80 grams H2O þ

  23. Regents Question: 01/04 #56-58 A student uses 200 grams of water at a temperature of 60°C to prepare a saturated solution of potassium chloride, KCl. Identify the solute in this solution. According to Reference Table G, how many grams of KCl must be used to create this saturated solution? This solution is cooled to 10°C and the excess KCl precipitates (settles out). The resulting solution is saturated at 10°C. How many grams of KCl precipitated out of the original solution? KCl 90 g Hint: 200 g of water was used – table G is for 100 g of water 30 g

  24. The addition of a nonvolatile solute to a solvent causes the boiling point of the solvent to increase and the freezing point of the solvent to decrease. The greater the concentration of particles, the greater the effect. (3.1qq)

  25. Regents Question: 06/03 #23 At standard pressure when NaCl is added to water, the solution will have a (1) higher freezing point and a lower boiling point than water (2) higher freezing point and a higher boiling point than water (3) lower freezing point and a higher boiling point than water (4) lower freezing point and a lower boiling point than water þ

  26. Regents Question: 01/04 #13 Compared to pure water, an aqueous solution of calcium chloride has a (1) higher boiling point and higher freezing point (2) higher boiling point and lower freezing point (3) lower boiling point and higher freezing point (4) lower boiling point and lower freezing point þ

  27. Energy can exist in different forms, such as chemical, electrical, electromagnetic, thermal, mechanical, and nuclear. (4.1a) Kinetic energy – the energy of motion Potential energy – the energy of position (stored energy)

  28. The amount of thermal energy contained in the molecules depends on how fast they are moving and how many molecules there are. • The total kinetic energy of all the molecules combined is called thermal energy • Thermal energy is a result of the Kinetic Energy of the molecules’ motion (molecules are always moving.) • Which can melt more ice: a small cup of hot water or a swimming pool of cold water?

  29. Heat is a transfer of energy (usually thermal energy) from a body of higher temperature to a body of lower temperature. Thermal energy is the energy associated with the random motion of atoms and molecules. (4.2a) • temperature The Law of Conservation of Energy states that energy can neither be created nor destroyed.

  30. Kinetic molecular theory (KMT) for an ideal gas states that all gas particles (3.4b): • 1. are in random, constant, straight-line motion. • 2. are separated by great distances relative to their size; the volume of the gas particles is considered negligible. • 3. have no attractive forces between them. • 4. have collisions that may result in the transfer of energy between gas particles, but the total energy of the system remains constant.

  31. Real Gases • Molecules do take up space • Molecules do attract each other • Energy is lost during collisions • Under conditions of high temperature and low pressure, real gases behave more like ideal gases • Small molecules take up little space and have weaker forces of attraction and are closer to an ideal gas • Hydrogen and helium are closest to being ideal gases

  32. Kinetic molecular theory describes the relationships of pressure, volume, temperature, velocity, and frequency and force of collisions among gas molecules. (3.4c) P1V1 P2V2 T1 T2

  33. Boyle’s Law Indirect Relationship between pressure and volume Temperature remains constant PxV = constant Charles’ law Direct relationship between volume and temperature Pressure remains constant V/T = constant Temperature must be Absolute temperature (Kelvins) Ideal Gas Laws

  34. Regents Question: 06/02 #14 Which graph shows the pressure-temperature relationship expected for an ideal gas? þ

  35. Graphing the gas laws As absolute temperature increases, pressure increases at constant volume Pressure Temperature As absolute temperature increases, volume increases at constant pressure Volume Temperature As pressure increases, volume decreases at constant temperature Volume Pressure

  36. Equal volumes of different gases at the same temperature and pressure contain an equal number of particles. (3.4e) Avogadro’s Hypothesis

  37. Regents Question: 06/02 #15 At the same temperature and pressure, which sample contains the same number of moles of particles as 1 liter of O2 (g)? (1) 1 L Ne(g) (3) 0.5 L SO2 (g) (2) 2 L N2 (g) (4) 1 L H2O(l) þ

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