staff.bbhcsd.orgstaff.bbhcsd.org/smithbeth/ap chem ch 11.pdf · • useful for determining molar...
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Vapor Pressure of SolutionsA nonvolatile SOLUTE lowers the vapor pressure of the solution.
The molecules of the solvent must overcome the force of both the other solvent molecules and the solute molecules.
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Freezing point depressionReason 1: As the water tries to freeze, the other molecules get in the way. Reason 2: By adding these other substances, you’ve added disorder to the mixture. Nature tends to favor disorder (entropy). When water tries to freeze, it has to get organized, which will be more difficult because it’s mixed with all of these other molecules.
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Osmotic Pressure (π)Osmosis is the selective passage of solvent molecules through a porous membrane from a dilute solution to a more concentrated one.
A semipermeable membrane allows the passage of solvent molecules but blocks the passage of solute molecules.
Osmotic pressure (π) is the pressure required to stop osmosis.
dilute moreconcentrated
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