Acids and Bases Flashcards
H+ transfer reactions are
reversible
Svante Arrhenius definition of acids/bases
an acid as a compound that dissolves in water to yield hydrogen cations (now recognized to be hydronium ions) and a base as a compound that dissolves in water to yield hydroxide anions.
Brønsted-Lowry acid
A compound that donates a proton to another compound
Brønsted-Lowry base
An acid-base reaction is, thus, the transfer of a proton from a donor (acid) to an acceptor (base).
Acid base reaction in terms of proton donor/acceptor….
An acid-base reaction is, thus, the transfer of a proton from a donor (acid) to an acceptor (base).
conjugate base
bc… talk abt reverse rxn
When an acid donates H+, the species that remains is called the conjugate base of the acid because it reacts as a proton acceptor in the reverse reaction
conjugate acid
when a base accepts H+, it is converted to its conjugate acid
acid ionization+ex with HF
The reaction between a Brønsted-Lowry acid and water to form hydronium ions is called acid ionization
For example, when hydrogen fluoride dissolves in water and ionizes, protons are transferred from hydrogen fluoride molecules to water molecules, yielding hydronium ions and fluoride ions:
Base ionization
occurs when it accepts protons from water molecules. In the example below, pyridine molecules, C5NH5, undergo base ionization when dissolved in water, yielding hydroxide and pyridinium ions:
acid and conjugate base relationship
Weaker the acid, stronger the conjugate base.
amphiprotic
Species capable of either donating or accepting protons
diff btwn bonsted lowery and arrhenius
bronsted: acid is proton doner
arrhenius: hydrogen
An Arrhenius acid increases hydrogen ion concentration.
autoionization of water
kw
at 25 °C, Kw has a value of 1.0 10−14.
The process is endothermic, and so the extent of ionization and the resulting concentrations of hydronium ion and hydroxide ion increase with temperature.
Kw
The Ion Product Constant of Water
what does it not include+when temp increase
the concentrations of solids and liquids are not included. Therefore, our expression for kw does not include the concentration of water, which is a pure liquid.
When temp increase the ph would be lower but same amount of oh and h ions. just bigger number concentration so when u multiply them for Kw you get larger KW.
Therefore, the sum of pH and
pOH will always be 14 at
25 degrees for any aqueous solutions
this relationship will not hold true at other temperatures, because kw is temperature dependent!
At 100°C, the pH of pure water is 6.14. That is the neutral point on the pH scale at this higher temperature. A solution with a pH of 7 at this temperature is …..bc…..
slightly alkaline because its pH is a bit higher than the neutral value of 6.14.
Ph formula
POH formula (2)
14-ph
OH- concentration formula
H3O+ concentration formula
10^-ph
at 25 degrees relate ph and poh
Since the autoionization constant Kw is——-, these correlations between pH values and the acidic/neutral/basic adjectives will be ——- at temperatures other than —.
temperature dependent
different
25 °C
If neutral solution neutral solutions exhibit pH = pOH = 6.31
then what do acidic solutions and basic solutions exhibit in terms of PH and POH? Less than 6.31?????
acidic solutions exhibit pH less than 6.31 and pOH greater than 6.31, whereas basic solutions exhibit pH greater than 6.31 and pOH less than 6.31.
acid-ionization constant, Ka+formula
the equilibrium constant for the ionization of an acid
The larger the Ka
the larger the concentration of h3O+
and A− relative to the concentration of the nonionized acid, HA, in an equilibrium mixture, and the stronger the acid.
A strong acid is strong when…. bc….
An acid is classified as “strong” when it undergoes complete ionization, in which case the concentration of HA is zero and the acid ionization constant is immeasurably large (Ka ≈ ∞).
percent ionization
+quadratic or assumption rule
if percent ionization is less than 5% you can use approximation but if its larger you need quadractic equation
The percent ionization of a weak acid
decreasing as concentration increases.
base-ionization constant (Kb) in aqueous solutions
In solutions of the same concentration, stronger bases ionize to a greater extent, and so yield higher hydroxide ion concentrations than do weaker bases. A stronger base has a larger ionization constant than does a weaker base
Ka, Kb, Kw relationship
acid/base/conjugate partner relationship
the stronger the acid or base, the weaker its conjugate partner
buffer
A solution containing appreciable amounts of a weak conjugate acid-base pair
resist changes when strong acid/bases are added
pka
+smaller it is….
+what it says abt the acid
+formula
how willing an acid is to give up a proton
smaller pka the stronger the acid
= -logKa
pka/pkb/pkw relationship
pKa+pKb=pKw=14
pka back to ka
ka=10^-pka
ph, pka and log formula that relates it all
