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SOLUTIONS• A solution is a
• The is(are) the substance(s) present in the
• The is the substance present in the
SOLVATION• The process by which an
is surrounded by solvent molecules arranged in a specific manner
• This
“LIKE DISSOLVES LIKE”• Two substances with similar
are likely to be in each other
• Non-polar molecules are soluble in–Ex.:
• Polar molecules are soluble in–Ex.:
• Ionic compounds are more soluble in–Ex.:
SOLUTION SATURATION• Saturated solution: contains the
amt. of a solute that will dissolve in a given amt. of solvent at
• Unsaturated solution: contains solute than a solvent has the capacity to dissolve at
• Supersaturated solution contains solute than is present in a saturated solution at
FACTORS AFFECTING SOLUBILITY1. Temperature: solubility of solids
and liquids generally • The solubility of gases generally
2. Pressure: solids and liquids are
• The solubility of a
(Henry’s LawHenry’s Law)
CONCENTRATION OF SOLUTIONS• The of a solution is
the amt. of solute present in a given quantity of solvent or solution
• Concentrated: (qualitative observation)
• Dilute: (qualitative observation)
• Standard Solution: a solution whose
CONCENTRATION UNITS• Molarity ( ): moles of solute per
liter solution ( )
• Molality ( ): moles of solute per kg solvent ( )
2 WAYS TO QUANTIFY RATIO OF SOLUTE PARTICLES TO SOLVENT• Molality, or molal concentration,
(m)–m =
• Mole fraction
DILUTIONS• Stock solutions: concentrated
solutions that are purchased or prepared to save time and space in the lab
• Solvent can be added to a to achieve a desired concentration to be used for a specific purpose
• Dilution:
COLLIGATIVE PROPERTIES OF SOLUTIONS• Colligative properties:
• Solutes that dissociate (i.e. ) have a greater effect than those that do not
• Ex.: 1 mol of MgCl2 would have more effect than 1 mol of NaCl which has more effect than 1 mol of glucose (C6H12O6). Why?!
DECREASE IN VAPOR PRESSURE• The addition of solute to a
solvent lowers the vapor pressure of the solvent
• Why?–Solvent particles surround solute
particles, which reduces the solvent’s kinetic energy
–Now solvent can’t “shoot out” into gas as often
BOILING POINT ELEVATION• The addition of solute to a solvent
raises the boiling point of the solvent
• Why?–Vapor pressure is reduced. More
heat is required to break intermolecular forces holding solvent in liquid phase
–NaCl in H2O when cooking pasta
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