Terms in this set (50)
does not have a uniform composition and the individual substances remain distinct
a mixture from which some of the particles settle out slowly upon standing. Can be separated by filtration
a heterogeneous mixture of intermediate sized particles (between 1 nm and 1000 nm) and do not settle out, nor can they be filtered apart.
a homogeneous mixture consisting of particles dissolved in a solvent
the dissolving medium and the most abundant substance in a solution
The most abundant substance in a mixture
the random movements of particles in a liquid colloid, from the results of particle collisions
the scattering of light by dispersed colloid and suspended particles
a substance that dissolves in a solvent
two liquids that are soluble in each other in any proportion
a substance that does not dissolve in a solvent
two liquids that can be mixed but separate shortly after
Solvation of Ions (NaCL dissolving in water)
NaCl crystals are surrounded by water molecules
Water's δ+ align with Cl- ions, δ- align with Na+ ions
Ionic bonds between Na & Cl are broken, IMFs formed between δ+ on water & Cl- and δ- and Na+
The new IMFS cause the ions to separate & dissolve
This is dissociation
Solvation of Polar Molecules
The IMFs holding the polar molecules in place in the crystal are broken and new IMFs between individual polar molecules and water are formed.
Solvation of Soaps and Detergent
Soaps and detergents are contain polar molecules, by adding the polar soap/detergent to a non-polar substance (i.e. grease) it will make the grease a polar substance, allowing for it to dissolve in a polar solvent (usually water)
heat of solution
The overall energy change that occurs during solution formation
the amount of a substance that dissolves in a given quantity of solvent
a solution containing a small amount of solute
a solution containing a large amount of solute. Concentration will increase if i) more solute is added, and/or ii) some solvent is evaporated
a solution that contains less solute than a solution is capable of dissolving at a given temperature and pressure. Looks clear.
a solution containing the maximum amount of solute for a given quantity of solvent at a constant temperature and pressure. Looks clear.
saturated with excess
If more solute is added it will not dissolve and an equilibrium exists between undissolved and dissolved solute. The amount of dissolved solute remains constant. The liquid looks clear and will have solid particles visible on the bottom. This is called a saturated solution with excess solute.
a solution that contains more solute than it can theoretically hold at a given temperature. Prepared by heating the solution to dissolve more solute then slowly cooling. Excess solute precipitates if a seed crystal is added. It looks clear, very unusual, easily disturbed. Looks clear.
How/why do solutes dissolve in water?
The positive sides of the water molecule are attracted to the negative ions while the negative side of the water molecule is attracted to the positive ion.
Do all ionic solids dissolve in water?
No, many do not. If the compound has a high lattice energy then not enough energy will be recouped making new IMFs with water and they are insoluble (e.g. carbonates, sulfates).
speed at which something dissolves.
Does solvation increase if you shake the mixture?
Yes, more mixing means more contact between the solute and solvent.
Does solvation increase if you crush the solid before dissolving it?
Yes, surface area of the solute is exposed to the solvent.
Does solvation increase if you cool the mixture?
No, heating gives molecules more kinetic energy making them move faster which weakens IMFs. Molecules move faster and further apart, allowing more contact between the solute and solvent. Cooling would do the opposite and slow down the solvation.
Does solubility increase if you increase the pressure (gases)
pressure increases, solubility of gas increases
e. g. soda - when you open the bottle, the gas "undissolves" so you see the bubbles
P ↑ solubility ↑
Henry's Law states that solubility (S) is directly proportional
to pressure (P):
S1 = P1
Does solubility increase if you increase the temperature (liquids and solids)
Yes, because IMFs are weakened so particles are more easily separated and there is greater mixing, therefore easier dissolving
Does solubility increase if you increase the temperature (gases)
No, because as temperature increases, solubility of gas decreases because increased T causes increased k. e., which weakens IMFs causing more molecules to escape, not dissolve.
That's why warm soda tastes flat, because CO2 has escaped.
Mass solute volume solute
x100 or x100
total mass solution total volume solution
M= mol solute
Mole Fraction (X)
Ratio of moles of solute to total number of moles
Molarity by dilituion
M1V1 = M2V2
m= moles solute
Compounds that conduct electricity when melted or dissolved in water (To have electricity it must have charged particles that are free to move)
Van't Hoff factor
is the number of (particles) formed when a compound dissolves (remember, ionics dissociate into ions)
Dissociation of IONIC Solids in Water
Ionic compounds are electrolytes, because they dissociate in water to form a solution that conducts electricity.
Strong electrolytes produce many ions
Weak electrolytes produce only a few ions
Dissociation of Molecular (Polar) Solutes in Water
Most molecular compounds are nonelectrolytes (don't dissociate nor conduct electricity), but exceptions exist, most importantly acids.
Properties of a substance that depend on the number of solute particles dissolved in solution
Vapor Pressure Lowering
The solvent now has to break additional IMFs which takes more energy. Fewer solvent molecules have kinetic energy to escape as a vapor. Also, solute molecules occupy spaces at the surface of the liquid which prevents solvent molecules leaving.
Freezing-point goes down when a solute is dissolved in a solvent. The presence of solute particles makes forming an orderly pattern in a solid harder and requires the molecules to release even more energy to form a solid. So the molecules slow down more and have less kinetic energy which means lower temperature, so FP decreases.
Boiling-point goes up when a solute is dissolved in a solvent. Additional kinetic energy is required for solvent particles to overcome the new IMFs formed between the solute and solvent at the surface and escape to become a gas.
Change in freezing point
freezing-point constant x molality x # van't Hoff factor
Change in boiling point
boiling-point constant x molality x # van't Hoff factor
the amount of additional pressure caused by water molecules that moved into the concentrated solution.