Chemistry - Chapter 19 Flashcards
conjugate acid
the ion or molecule formed when a base gains a hydrogen ion
conjugate base
the ion or molecule that remains after an acid loses a hydrogen ion
conjugate acid-base pair
consists of two ions or molecules related by the loss or gain of one hydrogen ion
amphoteric
give an example
a substance that can act as either an acid or a base
ex. HCl = water accepts a proton –> base
NH4 = water donates a proton –> acid
hydronium ion
(H3O) the positive ion formed when a water molecule gains a hydrogen ion
Bronsted Lowry Theory
where an acid is a hydrogen-ion donor and a base is a hydrogen-ion acceptor
self-ionization
a term describing the reaction in which two water molecules react to produce ions
neutral solution
what is the pH of this solution?
an aqueous solution in which the concentrations of hydrogen and hydroxide ions are equal
has a pH of 7.0
ion-product constant for water
(Kw) the product of the concentrations of the hydrogen ions and hydroxide ions in water
it is 1 x 10^-14 at 25°C
acidic solution
any solution in which the hydrogen-ion concentration is greater than the hydroxide-ion concentration
basic solution
any solution in which the hydroxide-ion concentration is greater than the hydrogen-ion concentration
pH
number used to denote the hydrogen-ion concentration, or acidity, of a solution
-log[H+] = pH
strong acid
an acid that is completely (or almost completely) ionized in an aqueous solution
weak acid
an acid that’s only slightly ionized in an aqueous solution
acid dissociation constant
(Ka) the ratio of the concentration of the dissociated form of an acid to the undissociated form
stronger acids have larger Ka values than weaker acids
strong base
a base that completely dissociates into metal ions and hydroxide ions in aqueous solutions
weak base
a base that reacts with water to form the hydroxide ion and the conjugate acid of the base
base dissociation constant
(Kb) the ratio of the concentration of the conjugate acid times the concentration of the hydroxide ion to the concentration of the base
neutralization reaction
a reaction in which an acid and a base react tin an aqueous solution to produce a salt and water
titration
process used to determine the concentration of a solution (often an acid or base) in which a solution of known concentration (the standard) is added to a measured amount of the solution of unknown concentration until an indicator signals the end point
standard solution
a solution of known concentration used in carrying out a titration
equivalence point
the point in a titration where the number of moles of hydrogen-ions equals the number of moles of hydroxide ions
end point
the point in titration at which the indicator changes color
List 3 rate of reaction factors:
Temperature
Concentration
Catalyst
What is the equilibrium-constant equation?
Keq = [D^d} [C^c} / [B^b] [A^a}
Arrhenius’s definition of acids and bases? (2)
acids are hydrogen containing compounds that ionize to yield hydrogen ions in aqueous solutions
bases are compounds that ionize to yield hydroxide ions in aqueous solutions
What is Le Chatelier’s Principle?
if a stress is applied to a system in dynamic equilibrium, the system changes in a way that relieves the stress
How are [H+] and [OH-] related in an aqueous solution?
the product of the hydrogen-ion concentration and the hydroxide-ion concentration equals 1.0 x 10^-14
** ion-product constant for water (Kw)
Equation to find the ion-product constant for water (Kw)
Kw = [H+] x [OH-] = 1.0 x 10^-14
Properties of water molecules (5)
highly polar
constantly in motion
+1 H2O molecule = H3O
-1 H2O molecule = [OH-]
Concentration of [H+] and [OH-] ions = 1.0 x 10^-7 M in pure water @ 25°C
What is the direction of the shift in equilibrium with the addition or loss of water
The equilibrium shifts towards the formation of water
[H+] ^ = v [OH-]
What can possibly change when finding the ion-product constant for water? (Kw)
What definitely won’t change?
Concentrations may change
Product stays the same
basic solutions are also called…?
alkaline solutions
How do you calculate the acid dissociation constant (Ka)?
Ka = [H+][A-] / [HA]
*equilibrium concentrations found with equilibrium constant formula
How do you calculate the base dissociation constant (Kb)?
Kb = [conjugate acid] x [OH-] / [base]
*equilibrium concentrations found with equilibrium constant formula
what do the words concentrated and dilute indicate?
what do they refer to?
they indicate how much of an acid or base is dissolved in solution
the number of moles of the acid or base in a given volume
how to find the pH of a substance?
pH = -log[H+]
how to find the [H+] of a substance? (when pH is not a whole number)
[H+] = 10^-pH (antilog)
low pH =
high pH =
more acidic
more basic
what is pH often measured with? (2)
acid-base indicators or a pH meter
how to find [OH-]?
how to find pOH?
[OH-] = 10^-pOH
pOH = -log v10[OH-]
Since [H+][OH-] = 1.0x10-14…. ?
pH + pOH = 14 (@25°C)
at what point in a titration does neutralization occur?
when the number of moles of hydrogen ions is equal to the number of moles of hydroxide ions
define salts
ionic compounds consisting of an anion (-) from an acid and a cation (+) from a base
