SOLUTIONS

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SOLUTIONS

• Section 8.1
• and 8.2

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SOLUTIONS

• SoluteA substance whose particles are dissolved
  in a solution
• SolventThe substance in which the solute
  dissolves
• The solution takes the state of the solvent

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Substances can dissolve in water in three ways

• DissociationAn ionic compound separates into
  ions as it dissolves
• DispersionThe process involves breaking into
  smaller pieces
• IonizationNeutral molecules gain or lose
  electrons

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PROPERTIES OF LIQUID SOLUTIONS

• The three physical properties of a solution that
  vary from those of its solute and solvent are
• Conductivity
• Freezing point
• Boiling point

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Solution

• During the formation of a solution, energy is
  either released or absorbed (endothermic and
  exothermic)

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FACTORS AFFECTING RATES OF DISSOLVING

• Surface areaThe greater the surface area, the
  more frequent the collisions occur which results
  in faster dissolving
• StirringStirring the solution allows for more
  collisions
• Increasing temperatureincreasing the temperature
  causes the particles in the solvent to move
  faster, thus there are more collisions

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SOLUBILITY AND CONCENTRATION

• Solubility is the maximum amount of solute that
  dissolves in a given amount of solvent and a
  constant temperature

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Three types of solutions

• Saturated solutions hold as much solute as the
  solvent can hold at a given temperature
• Unsaturated solutions have less than the maximum
  amount of solute that can be dissolved
• Supersaturated solutions contain more solute than
  it normally hold at a given temperature

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Solubility curve

• Which substance does not greatly increase,
  increases the most, decrease in solubility, as
  the temp is increased?
• If 50g of KCl are dissolved in 100g of water at
  50oC, what type of soln is formed?
• Which substance is the Most, Least soluble at
  0oC?
• Which 2 substances have the same solubility at
  60oC?
• At 30oC which substance, Pb(NO3)2 or KNO3, can
  form the more concentrated solution?

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FACTORS AFFECTING SOLUBILITY

• Polarity of the solventLike dissolves like
  meaning that a polar solvent will dissolve a
  polar solute
• TemperatureTemperature increases the solubility
  of a solid in a liquid but a gas becomes less
  soluble at higher temperatures
• PressureIncreasing the pressure on a gas
  increases its solubility in a liquid

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Concentration

• The concentration of a solution is the amount of
  solute dissolved in a specific amount of solution
  
• Conc Solute x 100
• Solution

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Concentration of solutions

• by volume Volume of solute x100
  Volume of solution
• Percent by MassMass of solute x 100
• Mass of solution

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Examples

• What is the concentration if solute 15mL and
  solution 100mL?
• A 300 mL solution contains 50mL of HCl dissolved
  in 250mL of water. What is the concentration of
  the HCl? What is the concentration of water?
• The relative humidity is 30. If you sample 1
  liter of this air how much of it is water vapor
  and how much of it is air?