Chapter 12: Solutions (sections 1 & 2) Flashcards
the composition of a solution is expressed as
concentration
conentration is always expressed as the quantity of .. present in a fixed quantity of the … or …
solute; solution; solvent
for most solutes, there is a limit to the quntity that can dissolve in a
fixed volume of a given solvent
the solubility of a solute is reached when the …. and the …. are equal
rate of dissolution; rate of crystallization
solubility is the concentration of solute that exists in equilibrium with an ….; that is, it is the maximum concentration that can … at a particular temperature
excess of that substance; dissolve
a saturated solution is one that is in equilibrium with
an excess of the solute
the concentration of a saturated solution is equal to the
solubility
an unsaturated solution is one in which the concentration of the solute is
less than the solubility
supersatured solutions have a concentration of solute that is
temporarily greater tahn its solubility
supersaturation is an … condition
unstable
two of the most important factors that determine whether a given substance will dissolve in a solvent include:
the enthalpy change that accompanies solute-solvent interactions
change in disorder
three types of intermolecular forces are involved in the formation of condensed phase solutions:
solute-solute, solvent-solvent, solute-solvent
(steps in solution formation) step 1 ΔH1: expanding the solute: separating the solute into
individual components; endothermic
(steps in solution formation) step 2 ΔH2: expanding the solvent: overcoming …. of the solvent molecules
intermolecular forces ;endothermic
(steps in solution formation) step 3 ΔH3: interaction of … and … to form the solution
solute; solvent; exothermic
enthalpy of solution=
ΔH1 + ΔH2 + ΔH3
heat of solution is the amount of heat energy absorbed or released when a
specific amount of solute dissolves in a solvent
many substances with positive enthalpies of solution still dissolve … due to an increase in .. (…) which is favorable
spontaneously; entropy; disorder
water surrounds ions in a
sphere of hydration
disorder increases significantly when ionic solids
dissolve in solution
the interaction of the ions with water molecules is called
hydration
pressure has very little effect on the solubilities of .. and ..
solids; liquids
the solubility of a gas is directly proportional to its …. at a …./ [a] is calculated via …
partial pressure; given temperature; henry’s law
henry’s law:
C=kP
an increase in pressure favors the
denser phase
for gaseous solutes, an increase in pressure is relieved by additional
gas dissolving in the liquid
le chatelier’s principle can be used to predict what is favored:
endothermic:
exothermic:
A + solvent + heat ↔ solution
B + solvent ↔ solution + heat
as temperature increases, the solubility … for any substance with an endothermic enthalpy of solution and … for one with an exothermic enthalpy of solution
increases; decreases
since the enthalpy of solution for most gases in water is exothermic their solubilities … with an increase in temperature
decrease
the solubilities of most solids … as the temperature of the solution increases
increases
some substances that appear to violate these generalizations undergo a more
complex dissolution process
the rte at whcih solids dissolve …. with increasing surface area of the solid
increases
solids tend to dissolve best when:
heated, stirred, ground into small particles
gases tend to dissolve best when: the solution is …, … is high
cold; pressure
