Solubility Graph Notes

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• Solubility Graph Notes

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Henrys Law

• Gaseous solutes increase solubility with
  increasing pressure.
• Pressure does not affect solubility of a solid.
• No matter how much pressure you put on a marble,
  its NOT going to dissolve in water!

pressure on gas then solubility of gas
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• Changing temperature and pressure changes the
  amount of solute that can dissolve.
• Solubility measures the amount of solute
  dissolved in a solvent at a certain temperature.

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Temperature and Solubility of Solids

• Temperature Solubility (g solute/100 g H2O)
• KCl(s) NaNO3(s)
• 0 27.6 74
• 20 C 34.0 88
• 50 C 42.6 114
• 100 C 57.6 182
• What is happening to the solubility of each of
  these solid solutes as temp. increases?

temp. solubility of solid
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Solubility of Solids

• as temperature increases solubility increases
• as temperature decreases solubility decreases
• This is what is known as a directly proportional
  relationship.

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Learning Check

• Can more sugar dissolve in tea when it is hot or
  cold? Explain your reasoning.

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Temperature and Solubility of Gases

• Temperature Solubility (g/100 g H2O)
• CO2(g) O2(g)
• 0C 0.34 0.0070
• 20C 0.17 0.0043
• 50C 0.076 0.0026
• What is happening to the solubility of these
  gaseous solutes as temperature increases?

temp. solubility of gas
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Solubility of Gases

• as temperature increases solubility decreases
• as temperature decreases solubility increases
• This is what is known as an inversely
  proportional relationship.

GASEOUS Solute
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Learning Check

• If it gets too hot on a summer day, why might
  many fish die resulting in fish kills?

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Lets Summarise (No, this is not in your notes)

• The 3 types of solutions are
• saturated solutions
• maximum amount of solute visible solute present
• unsaturated solutions
• less than maximum amount of solute no visible
  solute present
• supersaturated solutions
• unstable solution in which more solute is
  dissolved than normal
• solute precipitates out
• The type of solution depends on temperature (and
  pressure).

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• Solubility Curve graphs that plot solubility in
  grams of solute dissolved in 100 g H2O at certain
  temperatures.

• Solubility curves are the lines/curves on the
  graph which are made up by points.
• Points ON the curve represent saturated soln
• Points ABOVE the curve represent supersaturated
  soln
• Points BELOW the curve represent unsaturated soln

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• Thats all the notes for today!
• Lets practice!