Chpt 13: Properties of Solutions Flashcards
Ione pair???
What you call previously dissociated ions (like Na+ and Cl-) that have re-combined temporarily (bc of electrostatic attraction) in a sln, causing a slight shift the van’t Hoff “i” value
More common in diluted slns
what does the term Solubility describe?
amt of solute needed to form a saturated sln at a given temp, assuming that excess solute is present
amt that something dissolves in a given quantity of solvent
What does the term ‘solute’ describe in a solution?
the part/component of the solution in the smaller amount
exp. in salt water solution, salt is the solute
in the enthalpy of solution equation, is delta enthalpy of solvent endothermic or exothermic?
endothermic.
breaking bonds requires energy
what does Henry’s Law describe/quantify?
the impact of vapor pressure on the solubility of gases
What condition(s)/temperature does Boiling point describe?
the temp at which a liquid achieves vapor pressure of 1 atm
as solution-ness of a system goes up, entropy goes…
up
what is the van’t Hoff factor?
The number of fragments that a solute break up into for a particular solvent
represented by “i”
What does it mean to say that the formation of a solution is ‘spontaneous’?
that no energy had to be added to the system in order to facilitate the solution forming
is dissolution the same as dissociation?
no
what is a hydrate?
a compound, typically a crystalline one, in which water molecules are chemically bound to another compound or an element (even after the aq water is evaporated off)
Barring physical barriers between particles, do gas particles always spread out and form homogenous mixtures/solutions?
yes
what is the order of the intermolecular forces (listed from weakest to strongest)?
dispersion force dipole dipole force hydrogen bond ion dipole force ionic bond
what does Volatile/volatility describe?
the tendency of a substance to vaporize (r/t vapor pressure).
what does the term ‘dissociation’ describe?
when a solute is ionized in solution
What does the term ‘hydration’ describe?
solvation process in which water is the solvent
what is the formula for Henry’s Law?
Sg = kPg
solubility of gas = (k constant)(partial pressure of gas above sln)
What does solution formation have to do with entropy (disorder) and enthalpy (energy) in a system?
systems tend to try to decrease their entropy and increase their enthalpy; solution formation helps systems to achieve both
what is the Tyndell effect?
property/ability of colloids to scatter visible light
in the enthalpy of solution equation, is delta enthalpy of solute endothermic or exothermic?
endothermic.
breaking bonds requires energy
What 2 factors can inhibit a components in a system from forming a solution SPONTANEOUSLY?
- physical barriers
2. miss-matched intermolecular forces
what does it mean to call solution components ‘Immiscible’?
that the components will NOT mix together in all proportions
specifically applies to liquids (that don’t dissolve well in one another)
what is an Unsaturated solution?
a sln that has LESS solute than what is needed to achieve equilibrium
no undissolved solute left
what does it mean to call solution components ‘Miscible’?
that the components will mix together in all proportions
specifically applies to liquids (that dissolve well in one another)
what does the term ‘Supersaturated solution’ describe?
a sln that has more solute than what is needed to achieve equilibrium (because the sln was heated and then extra solute was added to it)
considered unstable
Do intermolecular forces (between particles) impact the likelihood of gas solution formation?
no. gases always mix.
intermolecular forces really only impact solution formation when considering liquids and solids.
Do exothermic processes tend to be spontaneous?
yes
What 2 conditions enable a solution process to be described as ‘spontaneous’?
- solution formation increases the systems’s entropy (disorder)
- solution formation decreases the system’s enthalpy (energy)
what is the term ‘crystallization’ meant to describe?
the opposite of solution formation;
when dissolved particles from a solid solute come back together to rejoin/reform the solid
what makes a solution ‘ideal’
when the solutes don’t experience any ion pairing
What does the term ‘solution process’ describe?
what happens when one substance disperses uniformly throughout another
in the enthalpy of solution equation, is delta enthalpy of mixture endothermic or exothermic?
exothermic.
making bonds releases energy
What does the term ‘solvent’ describe in a solution?
the part/component of the solution in largest amount
exp. in salt water solution, water is the solvent
what does the term ‘Saturated solution’ describe?
a solution in dynamic equilibrium
what is vapor pressure?
the pressure caused by liquid molecules that have taken on enough energy to escape into the gas phase and exert pressure onto the liquid
What 2 factors impact the likelihood that a solution will form?
- tendency towards mixing (tendency of components to mix/spread in the absence of barriers)
- intermolecular forces
what does the term ‘solvation’ describe?
interactions whereby ions are surrounded by solvent molecules due to attractive forces
what is a solution?
what you get when one substance disperses uniformly in another
what is a Colloid?
a type of mixture (somewhere between a homogenous mixture and a heterogenous mixture) whose solutes are big enough to scatter light but small enough to not experience gravity
how is moLALity described?
moles (of solute) per kg (of solvent)
what is osmotic pressure?
the pressure that must be applied to resist the pressure of a pure solvent moving across a membrane into a solution
How do you calculate the vapor pressure for a solution made of TWO volatile substances? (exp. water and ethanol)
you have to do:
mole fraction solvent * vapor pressure of pure solvent) + (mole fraction solute * vapor pressure pure solute
what does the term ‘Dynamic Equilibrium’ describe?
when the rate of dissolution and crystallization in a solution are equal, and the amount of solute stays the same
as solution-ness of a system goes up, enthalpy goes
down
