chapter 13 Flashcards
(36 cards)
what is a solution?
homogenous mixture of at least two substances
what is a saturated solution?
contains the maximu amount of a solute that will dissolve in a solvent at a specific temperature
what is solubility?
the amount of solute dissolved in a given volume of a saturated solution
what is an unsaturated solution?
contains less solute than it has the capacity to dissolve
what is a supersaturated solution?
contains more dissolved solute than is pesent in a saturated solution. it is UNSTABLE
how does solubility increase in a more heated solution?
hydrogen bonds will break, resulting in less bonds and more interactions to make with the solute
what are the types of solutions?
what is solvation?
when the solute dissolves in the solvent, molecules of the solute disperse throughut the solvent. they are separated from one another and each solute molecule is surrounded by solvent molecules through this process
what does the breaking of solute molecules depend on?
- solute-solute interactions
- solvent-solvent interactios
- solute-solvent interactions
which intermolecular forces are involved in the solute-solvent interactions?
- ion-dipole
- dipole-induced dipole
- ion-induced dipole
Dissolution tends to be encouraged when it is __________ and discouraged when it is _____________
exothermic, endothermic
what is one factor that influences solubility?
thermicity
what does the phrase “like dissolves like” mean?
it means that two substances with intermolecular forces of similar type and magnitude are likely to be soluble in each other since their mixing is probably not endothermic
what does it mean when two mixtures are said to be miscible?
that they are completely soluble in each other in all proportions
what is the enthalpy change when dissolution is favored?
negative (exothermic)
which factor influences dissolution?
change in the system’s entropy
when does a system have a higher entropy? lower entropy?
- when a system’s particles are free-ranging and mobile (liquid)
- when a system’s particles are tightly-confined and immobile (crystalline solid)
what is entropy?
measure of disorder
what is the second law of thermodynamics?
the entropy of the universe tends to increase in natural, spontaneous process
what happens when the reaction is endothermic and dissolution occurs?
the dissolution increases the potential energy of the system
what is molality?
number of moles of solute dissolved in 1 kg (1000g) of solvent
what is percent by mass?
ratio of the mass of a solute to the mass of the solution, multiplied by 100%
what is the advantage of molality?
it has the advantage of being temperature independent
what is the advantage of percent by mass?
Percent by mass is similar to molality in that it is independent of temperature. Furthermore, we do not need to know the molar mass of the solute to calculate the percent by mass.
