Chapter 12 Flashcards
EQUATION Molarity
moles of solute / liters of solution
EQUATION Molality
moles of solute / kilograms of solvent
Molarity is dependent on ____, while molality is dependent only on ____.
temperature, mass.
What product emitted by human activity contributes to the disintegration of corals and shells?
CO2
The ___ of a solution dictates its state.
solvent
Percent composition, or (part/whole) x 100, is the same as saying
parts per hundred.
A mole fraction, x_i, is
the moles of component i / total moles in the system
The sum of each component’s mole fractions equals
1.
A mole percent is
mole fraction x 100
What four forces can contribute to or fight dissolution?
Dipole-dipole, hydrogen bonds, dispersion, ion-dipole
In order for dissolution to occur, the _________ interactions must be _______ both the solute-solute interactions and the ________ interactions.
solute-solvent, greater than or equal to, solvent-solvent
T/F: A positive ΔH for a reaction means that it is endothermic. For a solution, that means that dissolution is unfavorable and will not occur.
F. Sometimes, even a reaction with a positive ΔH will occur - but generally, they won’t.
A reaction with a ΔH of zero is referred to as
an ideal solution
T/F: If two substances are mixed and successfully form a solution, they volume of that solution will be greater than that of the two substances measured separately.
F. The two substances form a solution because of mutual attraction, so the solution’s volume will be less.
How do micelles form?
They are spheres of detergent that form with the detergent’s hydrophobic tails on the inside and its hydrophilic heads on the outside.
T/F: A solution is bound by rules of dynamic equilibrium, which is reaches upon saturation of the solute. Dynamic equilibrium can be reached even when not all solute has dissolved if the solution is saturated already.
T
Solubility for gases in water is usually better at ____ temperatures.
Solubility for solids in water is usually better at ____ temperatures.
lower (because at higher temperatures, the water will start to evolve gas, too), higher.
EQUATION Solubility
S [solubility] = k [constant] x P [pressure of the gas]
The solubility equation is referred to as ____ law and fails if the gas _________.
Henry’s, reacts with the solvent.
Colligative properties depend on a substance’s ______ only.
concentration
What are the four colligative properties?
Vapor pressure, osmotic pressure, freezing point depression, boiling point elevation
Vapor pressure is the ability for the solvent to ________, which depends on the solution being in dynamic equilibrium. Adding solute to a solvent ____ its vapor pressure.
evaporate, stymies (lowers)
EQUATION Raoult’s law
P_a [vapor pressure of solvent above solution] = x_a [mole fraction of the solvent] x p˚_a [vapor pressure of the pure solvent]
Why does fractional distillation work?
To distill and keep a volatile component, just make it evaporate - the vapor will have more of the volatile component. Distill that vapor, and continue, until it is as pure as you’d like.
