Chapter 13: Properties of Sultions Flashcards
What are the 2 factors affecting the ability of substances to form solutions?
natural tendency for substances to mix | intermolecular interactions
How does mixing of gases happen spontaneously?
due to entropy (S)
What are the 3 kinds of intermolecular interactions involved in solution formation?
solute-solute interactions | solvent-solvent interactions | solvent-solute interactions
What are the solute-solute interactions?
between solute particles = need to overcome them in order to disperse the solute particles within the solvent
What are solvent-solvent interactions?
between solvent particles = need to overcome them to make room for the solute particles in between the solvent molecules
What are the solute-solvent interactions?
between solute and solvent particles = need to occur as they mix
What is solvation?
interaction that occurs when solute is surrounded by solvent molecules
What is hydration?
solvation interaction when solvent is H2O
What are hydrates?
solid compounds with a defined number of water molecules within the crystal lattice
What is crystallization?
when solute particles collide with the surface of a solute solid and reattach
What is a saturated solution?
solution that is in equal equilibrium with undissolved solute
What is solubility?
MAX amount of solute that can dissolve in a given quantity of solvent to form a saturated solution
What is an unsaturated solution?
less solute dissolved than the amount needed to form a saturated solution
What is a supersaturated solution?
solvent holding more solute than is normally possible at that temperature | unstable solutions
How can crystallization occur with a super saturated solution?
by adding a “seed of crystal” or scratching the side of a flask
What are the 3 factors affecting solubility?
solute-solvent interactions | pressure | temperature
How does solubility affect solute-solvent interactions?
increase in solubility is due to stronger attractions between solute and solvent molecules
What is miscible?
liquids that mix in all proportions
What is immiscible?
liquids that don’t mix in one another
How does pressure affect the solubility of a gaseous solution?
increase in partial pressure above the solvent = increases solubility of a gas in solvent
What is Henry’s Law?
solubility of a gas in a liquid solvent increases in direct proportion to the partial pressure of the gas above the solution
How does temperature affect solubility?
increase temp(T) = increase solubility of solids in water BUT decreases solubility of gases in water
What is dilute?
small concentration of solute
What is concentrated?
large concentration of solute
What are ppm (parts per million) and ppb (per billion) used for?
to express concentrations of very dilute solutions
What can you use to convert between Molarity and molality?
density
What is the difference between molarity and molality?
molaRity = depends on the VOLUME of solution; varies with temp(T) changes | molaLity = depends on MASS of solvent; doesn’t vary with temp(T)
What are colligative properties of a solution?
depend on the collective effect of the number of solute particles
What does “colligative” mean?
“depending on the collection”
What are the 4 kinds of colligative properties?
vapor-pressure lowering | boiling-point elevation | freezing-point depression | osmotic pressure
What is a non-volatile substance?
no measurable vapor pressure
What does Raoult’s Law state?
vapor pressure of a volatile solvent above a solution containing a nonvolatile solute is proportional to the solvent’s concentration in the solution
What is vapor-pressure lowering?
When a nonvolatile solute is added to a volatile pure solvent, the vapor pressure of the solvent (above the resulting solution) is lower than the vapor pressure above the pure solvent.
What is boiling-point elevation?
the boiling point of a solution is HIGHER than that of the pure solvent due to vapor-pressure lowering | higher temp is now needed to reach a vapor pressure of 1atm
What is freezing-point depression?
freezing point of solution is LOWER than that of the pure solvent due to vapor-pressure lowering | lower temp is now needed to reach a vapor pressure of 1atm
What is the van’t Hoff factor (i)?
number of fragments that a solute breaks up into for a particular solvent
What is the van’t Hoff factor for non-electrolytes?
1
What is the van’t Hoff factor for electrolytes?
depends on how the substance ionizes
What is osmosis?
net movement of solvent molecules from low [solute] –> high [solute] (to even things out)
What is osmotic pressure?
the pressures that stops osmosis
What are the 3 types of of solutions in osmosis?
isotonic | hypertonic | hypotonic
What is an isotonic solution?
same osmotic pressure of solvents and solutes = solvent passes through semi-permeable membrane at the same rate both ways
What is a hypertonic solution?
high osmotic pressure = solvent enters solution at a higher rate than leaving
What is a hypotonic solution?
low osmotic pressure = solvent enters solution at a slower rate than leaving
What are colloids?
suspensions of particles larger than individual ions or molecules, but TOO small to be settled out by gravity
What is the Tyndall effect?
phenomenon illustrating the ability of colloidal particles to scatter rays of light
What regions do colloids have?
hydrophobic and hydrophilic regions
