Ch 13 Section 1 Flashcards
solid compounds can be
ionic or molecular
in an ionic solid, a crystal structure is made up of .. held together by …
charged particles; ionic attractions
in a molecular solid, molecules are composed of
covalently bonded atoms
the solid is held togher by …, … forces
noncovalent; intermolecular
when they dissolve in water, ionic compounds and molecular compounds behave
differently
when a compound that is made of ions dissolves in water, the
ions separate from one another
this separation of ions that occurs when an ionic compound dissolves is called
dissociation
assuming 100% dissociation, a solution that contains 1 mol of sodium chloride contains .. of Na+ ions and … of Cl- ions
1 mol; 1 mol
a solution that contains 1 mol of calcium chloride contains .. of Ca2+ ions and … of Cl- ions
1 mol; 2 mol
although no ionic compound is completely insoluble, compounds of very low solubility can be considered … for most …
insoluble; practical purposes
it is difficult to write solubility rules that cover all
possible conditions
most sodium compounds are
soluble
most phosphates are
insoluble
dissociation equations cannot be written for
insoluble compounds
if the mixing results in a combination of ions that forms an insoluble compound, a … reaction and … will occur
double-displacement; precipitation
precipitation occurs when the attraction between the ions is greater than the attraction between the
ions and surrounding water molecules
to decide whether a precipitate can form, you must know the
solubilities of these two compounds
reactions of ions in aqueous solution are usually represented by … rather than…
net ionic equations; formula equations
a net ionic equation includes only those compounds and ions that undergo a
chemical change in a reaction in an aqueous solution
to write a net ionic equation, you first convert the chemical equation into an
overall ionic equation
all soluble ionic compounds are shown as
dissociated ions in solution
the precipitates are shown as
solids
ions that do not take part in a chemical reaction and are found in solution both before and after the reaction are
spectator ions
to convert an ionic equation into a net ionic equation, the … are … on both sides of the equation
spectator ions; canceled
some molecular compounds can also form
ions in solution (polar compounds)
ions are formed from solute molecules by the action of the solvent in a process called
ionization
the more general meaning of ionization is the creation of
ions where there were none
when n ionic compound dissolves, the ions that were already present
separate from one another
when a molecular compound dissolves and ionizes in a polar solvent, ions are formed where
non existed in the undissolved compound
like all ions in aqueous solution, the ions formed by such a molecular solute are
hydrated
the energy released as heat during the hydration of the ions provides the energy needed to
break the covalent bonds
the extent to which a solute ionizes in solution depends on the strength of the bonds within the .. and the strength of attraction between the …
molecules of the solute; solute and solvent molecules
if the strength of a bond within the solute molecule is weaker than the attractive forces of the solvent molecules, then the covalent bond of the solute … and the …
breaks; molecule is separated into ions
HCl is a molecular compound that
ionizes in aqueous solution
the attraction between a polar HCL molecule and the mpolar water molecules is strong enough to break the HCL bond, forming
hydrogen and chloride ions
many molecular compounds contain a hydrogen atom bonded by a
polar covalent bon d
some of these compounds ionize in an aqueous solution to release
H+
the H+ ion attracts other molecules or ions so strongly that it does not normally
exist alone
the ionization of hydrgoen chloride in water is better described a a chemical reaction in which a proton is transferred directly from HCl to awater molecule, where it becomes
covalently bonded to oxygen and forms H3O+
the H3O+ ion is known as the
hydronium ion
the reaction of the H+ ion to form the hydronium ion produces much of the energy needed to
ionize a molecular solute
substances that yield ions and conduct an electric current in solution are
electroylytes
substances that do not yield ions and do not conduct an electric current in solution are
nonelectrolytes
the hydrogen halides are all molecular compounds with single
polar-covalent bonds
all hydrogen halides are gases, all are very solubler in water, and all are
electrolytes
HCl, hydrogen bromide, and HI strongly conduct an
electric current in an aqueous solution
however, hydrogen fluoride only weakly conducts an electric current at the
same concentration
the strength with which substances conduct an electric current is related to their
ability to form ions in solution
HCL, hydrogen bromide, and hydrogen iodide are 100% ionized in
dilute aqueous solution
a strong electrolyte is any compound whose dilute aqueous solutions
conduct electricity well
the conductivity of strong electrolytes is due to the presence of all or almost all of the dissolved
compound in the form of ions
HCL, hydrogen bromide, and HI are all
acids in aqueous solution
these acids, several other acids, and all soluble ionic compounds are
strong electrolytes
the distinguishing feature of strong electrolytes is that to whatever extent they dissolve in water, they
yield only ions
for example, some strong electrolytes, such as NaCL, may be highly soluble in water and form
ions in solution
others may not dissolve much, but the amount that does dissolve exists solely as
ions in solution
some molecular compounds form aqueous solutions that contain not only dissolved ions but also some dissolved molecules that are not
ionized
HF dissolves in water to give an acidic solution known as
hydrofluoric acid
However, the HF bond is much stronger than the bonds between
hydrogen and other halogens
when HF dissolves, some molecules
ionize
but the reverse reaction–the transfer of H+ ions back to F- ions to form hydrogen fluoride molecules–
also takes place
hydrogen fluoride is an example of a
weak electrolyte
a weak electrolyte is any compound whose dilute aquous solutions conduct
electricity poorly
the poor conductivity of weak electrolytes is due to the presence of a small amount of the
dissolved compound in the form of ions
this is in contrast to a nonelectrolyte which dissolves but does not produce any
ions in solution
another example of a weak electolyte is CH3COOH,
acetic acid
the description of an electrolyte as strong or weak must not be confused with the description of a solution as
concentrated or dilute
strong and weak electolytes differ in the degree of
ionization or dissociation
concentrated and dilute solutions differ in the amount of
solute dissolved in a given quantity of a solvent
hydrochloric acid is always a
strong electrolyte
acetic acid is always considered a
weak electrolyte
