Ch 9,10,11- Solutions, AcidBase, Redox Flashcards
“Incidentally, gases “dissolved” into other gases can be thought of as solutions, but are more properly defined only as ______because gas molecules do not interact all that much chemically, as described by the kinetic molecular theory of gases.
Mixtures
As a point of clarification: all solutions are considered mixtures, but not all mixtures are considered solutions.”
“is the component of the solution that remains in the same phase after mixing. If the two substances are already in the same phase (for example, a solution of two liquids), it is the component present in greater quantity”
Solvent
“is the electrostatic interaction between solute and solvent molecules. This is also known as dissolution, and when water is the solvent, it can be called hydration”
Solvation
“The dissolution of gases into liquids, such as CO2 into water, is an ______ process because the only significant interactions that must be broken are those between water molecultes
Exothermic
“CO2, as a gas, demonstrates minimal intermolecular interaction. Le Châtelier’s principle tells us this is the reason that lowering the temperature of a liquid favors solubility of a gas in the liquid.”
“When the new interactions are weaker than the original ones, solvation is_______ and the process is favored at ______ temperatures.
Endothermic; high
Most dissolutions are of this type. Two such examples have already been given: dissolving ammonium nitrate or sugar into water. Because the new interactions between the solute and solvent are weaker than the original interactions between the solute molecules and between the solvent molecules, energy (heat) must be supplied to facilitate the formation of these weaker, less stable interactions.”
“At constant temperature and pressure, entropy always ____ upon dissolution”
Increases
“the overall dissolution of table salt into water is ________ and favored at high temperatures.”
Endothermic
“The formation of these ion–dipole bonds is exothermic, but the magnitude is slightly less than the energy required to break the ionic bonds and hydrogen bonds
“ The ________ of a substance is the maximum amount of that substance that can be dissolved in a particular solvent at a given temperature. ”
Solubility
“When this maximum amount of solute has been added, the dissolved solute is in equilibrium with its undissolved state, and we say that the solution is saturated.”
“When this maximum amount of solute has been added, the dissolved solute is in equilibrium with its undissolved state, and we say that the solution is
saturated.”
“A solution in which the proportion of solute to solvent is small is said to be _______, and one in which the proportion is large is said to be ________”
Small; Concentrated
“In general, solutes are considered soluble if they have a molar solubility above _____ in solution.”
0.1 M
“In aqueous solutions, there are ____ general solubility rules:”
7
- All salts containing ammonium (NH4+) and alkali metal (Group 1) cations are water-soluble.
- All salts containing nitrate (NO3−) and acetate (CH3COO−) anions are water-soluble.
- Halides (Cl−, Br−, I−), excluding fluorides, are water-soluble, with the exceptions of those formed with Ag+, Pb2+, and HG22+.
- All salts of the sulfate ion (SO42−) are water-soluble, with the exceptions of those formed with Ca2+, Sr2+, Ba2+, and Pb2+.
- All metal oxides are insoluble, with the exception of those formed with the alkali metals, ammonium, and CaO, SrO, and BaO, all of which hydrolyze to form solutions of the corresponding metal hydroxides.
- All hydroxides are insoluble, with the exception of those formed with the alkali metals, ammonium, and Ca2+, Sr2+, and Ba2+.
- All carbonates (CO32−), phosphates (PO43−), sulfides (S2–), and sulfites (SO32−) are insoluble, with the exception of those formed with the alkali metals and ammonium.”
- All salts containing ammonium (NH4+) and alkali metal (Group 1) cations are water ______
Soluble
“All salts containing nitrate (NO3−) and acetate (CH3COO−) anions are also water-soluble.”
“Halides (Cl−, Br−, I−), excluding fluorides, are water-______, with the exceptions of those formed with
Soluble;
Ag+, Pb2+, and HG22+.”
“All salts of the sulfate ion (SO42−) are water-______, with the exceptions of those formed with”
Soluble
Ca2+, Sr2+, Ba2+, and Pb2+
“All metal oxides are _____, with the exception of those formed with
Insoluble; the alkali metals, ammonium, and CaO, SrO, and BaO”
“All hydroxides are ________, with the exception of those formed with
insoluble; the alkali metals, ammonium, and Ca2+, Sr2+, and Ba2+.”
All carbonates (CO32−), phosphates (PO43−), sulfides (S2–), and sulfites (SO32−) are ______, with the exception of those formed with
Insoluble; the alkali metals and ammonium.”
—refers to a molecule in which a cation is bonded to at least one electron pair donor (which could include the water molecule). The electron pair donor molecules are called _________.”
“complex ion—or coordination compound; Ligand
“Complexes are held together with coordinate covalent bonds, in which an electron pair donor (a Lewis base) and an electron pair acceptor (a Lewis acid) form very stable Lewis acid–base adducts”
“In some complexes (complex ion), the central cation can be bonded to the same ligand in multiple places. This is called _______, and it generally requires large organic ligands that can double back to form a second (or even third) bond with the central cation”
Chelation
“Chelation therapy is often used to sequester toxic metals (lead, arsenic, mercury, and so on)”
What is percent composition by mass?
Mass of solute/mass of solution
“Percent composition is used not only for aqueous solutions, but also for metal alloys and other solid-in-solid solutions.”
“The mole fraction (X) of a compound is given by the equation”
Moles of A/Total moles of all species
Define molarity
Moles of solute/Liters of solution
Define molality
Moles of solute/kg of solvent
“For dilute aqueous solutions at 25°C, the molality is approximately equal to molarity because the density of water at this temperature is 1 kg/L
“You won’t use molality very often, so be mindful of the special situations when it is required: boiling point elevation and freezing point depression.”