Exam One Vocabulary Flashcards
solution
homogeneous mixture of two or more pure substances, can be in any phase, clear as fluids (gas or liquid), can have color
solvent
solute dissolves in, most abundant solution component, usually determines solution phase
solute
substance that dissolves, less abundant solution component
not solutions
suspensions, colloidal dispersions
suspension
solid particles in a fluid (gas or liquid), appear cloudy, eventually separates upon standing or with centrifuge
e.s.d
equivalent spherical diameter
e.s.d of suspensions
> 0.2 µm
colloidal dispersion
appears cloudy, does not separate upon standing
colloid e.s.d
solid with e.s.d between 0.001 µm and 0.20 µm
enthalpy
systems ability to change heat, can be positive or negative
positive enthalpy
endothermic
negative enthalpy
exothermic
endothermic
contributes to increase in E, DOES NOT favor spontaneity
exothermic
contributes to decrease in E, favors spontaneity
entropy
indication of systems disorder
positive entropy
means decrease in system E, favors spontaneity
negative entropy
means increase in system E, DOES NOT favor spontaneity
electrolytes
a substance that forms an aqueous solution that conducts current, type of solute, creates mobile charge carriers in water, ionic compounds
charge carriers
dissolved ions
strong electrolytes
complete dissociation
weak electrolytes
partial dissociation, covalent solutes
non electrolyte
solute that forms a nonconducting solution in water, dissolve but do not dissociate into ions, molecular solute
solubility
describes the amount of solute that will dissolve, specific to a solute/solvent combination and condition, max. amount of solute that will dissolve in a given amount of solution
saturated solution
contains max. amount of solute, contains the dissolved solute in equilibrium with the undissolved, pure solute
undersaturated solution
less than max. solute dissolved
supersaturated solution
contains more than max. dissolved solute, disequilibrium, unstable state, formed from saturated solutions following a change of conditions (pressure and temperature)
solute-solvent interactions
substances with similar intermolecular forces form solutions
miscible
two liquids that form a solution when mixed
immiscible
two liquids that DONT form a solution, separate into layers when mixed
pressure
important for the solubility of gases in liquids, all gases in contact will dissolve
Henry’s Law
Cg = kPg
C (Henry’s Law)
concentration of the dissolved gas in the liquid solution
k (Henry’s Law)
Henry’s Law constant, specific to solute-solvent combination (usually H2O), temperature dependent
P (Henry’s Law)
partial pressure of the gas in the gas phase O2
Pg = XgPtot (what is X)
mol formation of gas
temperature effects on solids in liquid solutions
increase in T = increase in S
temperature effects on gases in liquids
increase in T = decrease in S
colligative properties
properties of solutions that depend only on the amount of solute present
units of concentration
mole fraction (X) and molality (m)
Xsolute
mols solute/total mols of solution
Xsolvent
mols solvent/mols solution
molality
mols/kg
vapor pressure
pressure exerted by the vapor phase of a substance in equilibrium with the liquid phase of that substance
lowering of vapor pressure
lowered by the presence of a non volatile solute
non volatile
doesn’t exert vapor pressure
Raoults Law
Pa=XaPa
Pa (Raoults Law)
vapor pressure of A from solution
Xa (Raoults Law)
mol fraction of substance A
(solvent)
Pa (at end of Raoults Law)
vapor pressure of pure A
boiling point
temperature at which vapor pressure of the liquid equals external pressure
boiling point elevation (equation)
ΔTb = kb x m
ΔTb (boiling point elevation)
change in boiling point
kb (boiling point elevation)
boiling point elevation constant, tabulated, specific to solvent
m (boiling point elevation)
molality
osmosis
movement of solvent molecules through a semi-permeable membrane in response to a concentration gradient
osmosis pressure (Π)
the pressure required to prevent osmosis into a solution relative to the pure solvent (physical force overrides the spontaneity)
osmosis pressure equation
Π = MRT
M (osmosis pressure)
molarity (mols/L)
R (osmosis pressure)
constant (0.0821 L x atm/mol x k)
T (osmosis pressure)
temperature
Van’t Hoff factor (i)
accounts for association of electrolytes
reaction rates
change in reactant or product amount over time
kinetics
study of reaction rates
characteristics of reaction rates
defined as positive numbers
change over time
depend on:
amount (or concentration) of reactant
temperature
catalyst
surface area (of reactants & catalyst)