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Definitions
Solution - Solution - homogeneous mixture
Solvent Solvent - present in greater amount~ does the dissolving.
Solute Solute - substance being dissolved
Types of Solutions
Based on state of solvent. All solid-liquid-gas combos are possible. EX: dental amalgam (alloy of liquid
mercury and a powder containing silver, tin, copper, zinc and other metals.) liquid solute, solid solvent solid solution
Nonliquid Solutions Solutions can be
gasses or solids. Example: Air you
breathe is a solution! 78% Nitrogen 21% Oxygen 1% Other gases
(argon, carbon dioxide, hydrogen…)
Example: Bronze is a solid solution of copper and tin!
Dissolving SolvationSolvation
occurs at the surface of the solute
solvent particles surround solute particles (+/- attraction)
solute particles are pulled into solution
Rate of Dissolving
Solids dissolve faster...Solids dissolve faster...
more stirring
small particle size(increased surface area)
high temperature
Rate of Dissolving
Gases dissolve faster...Gases dissolve faster...
no shaking or stirring
high pressure
low temperature
Solubility SolubilitySolubility
maximum grams of solute that will dissolve in a given amount of solvent at a given temperature
Concentration Concentrated solutionConcentrated solution
large amount of solute
Dilute solutionDilute solution small amount of solute
Precise Concentrations Percent by VolumePercent by Volume
Usually liquid in liquid EX: 10% juice = 10mL juice + 90mL water
Percent by MassPercent by Mass Usually solid in liquid EX: 20% NaCl = 20g NaCl + 80g water
Concentration
SATURATED SOLUTION
no more solute dissolves
UNSATURATED SOLUTIONmore solute dissolves
SUPERSATURATED SOLUTIONbecomes
unstable, crystals form
concentration
Solubility
Solids are more soluble at...Solids are more soluble at... high temperatures.
Gases are more soluble at...Gases are more soluble at... low temperatures. high pressures (Henry’s
Law).
Electrolytes
ElectrolyteNon-
Electrolyte
Electrolytes are compounds that break apart in water, forming charged particles (ions) that can conduct electricity.
- +
salt
- +
sugar
- +
acetic acid
WeakElectrolyte
Electrolytes
DissociationDissociation separation of +/- ions
when an ionic compound dissolves in water
Forming Electrolytes
1. Ionization1. Ionization breaking apart of polar
covalent molecules into ions when dissolving in water
2. Dissociation Process in which an
ionic solid separates into it’s positive and negative ions.
Colligative Properties Colligative properties- properties of
solutions that depend only on solute concentration
Freezing Point DepressionFreezing Point Depression solutes lower the freezing point of a solvent
Boiling Point ElevationBoiling Point Elevation solutes raise the boiling point of a solvent
Colligative Properties
Effect increases as the solute concentration increases.
Uses:Uses: antifreeze making ice cream salting icy roads
When Water Won’t Work! Water is referred to as the “Universal
Solvent” because it can dissolve many things… But~ not everything!
Oil for example!
“Like Dissolves Like” DetergentsDetergents
polar “head” with long nonpolar “tail”
can dissolve both types
Versatile Alcohol Ethanol is a molecule that can form
solutions with both polar and non polar solutes because ethanol molecules have both a polar and a non polar end.
How Soap Works Oils on human skin and hair help them
from drying out, but oils attract and hold dirt too.
Water alone cannot remove the dirt and oil because water is polar and the oil/dirt mixture is non polar.
Soap helps because it has an ionic (charged) end that will dissolve in water, and a long hydrocarbon portion that will dissolve in oily dirt.