Solutions PAK 10

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SolutionsPAK 10
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Some Definitions

• A solution is a homogenous mixture of 2 or more
  substances.
• One constituent is usually regarded as the
  SOLVENT and the others as SOLUTES.

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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

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Aqueous Solution

• A solution with water as the solvent and an ionic
  compound as the solute.

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Definitions

• Solutions can be classified as
• saturated or unsaturated.
• A saturated solution contains the maximum
  quantity of solute that dissolves at that
  temperature.
• An unsaturated solution contains less than the
  maximum amount of solute that can dissolve at a
  particular temperature

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Definitions

• SUPERSATURATED SOLUTIONS contain more solute than
  is possible to be dissolved
• Supersaturated solutions are unstable. The
  supersaturation is only temporary, and usually
  accomplished in one of two ways
• Warm the solvent so that it will dissolve more,
  then cool the solution
• Evaporate some of the solvent carefully so that
  the solute does not solidify and come out of
  solution.

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Solubility Curve
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Concentration of Solute

• The amount of solute in a solution is given by
  its concentration.

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Website Practice
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PROBLEM Dissolve 5.00 g of NiCl26 H2O in
enough water to make 250 mL of solution.
Calculate the Molarity.
Step 1 Calculate moles of NiCl26H2O
Step 2 Calculate Molarity
NiCl26 H2O 0.0841 M
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USING MOLARITY
What mass of oxalic acid, H2C2O4, is required to
make 250. mL of a 0.0500 M solution?
moles ML

• 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

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Preparing Solutions

• Weigh out a solid solute and dissolve in a given
  quantity of solvent.
• Dilute a concentrated solution to give one that
  is less concentrated.
• M1V1 M2V2

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Factors Affecting Solution Formation

• Temperature
• Particle Size
• Agitation