Unit 2: Acids and Bases Flashcards
Arrhenius Definition: Acids are compounds which break apart (ionize or dissociate) to give off an ________ ion (which combines with water to form the __________________-)
H+
hydronium ion, H3O+
Arrhenius Definition: Bases are compounds that break apart (ionize or dissociate) to give off a __________________-
hydroxide ion, OH-
Note that you will sometimes see the HCl equation written this way:
HCl (aq) → H+ (aq) + Cl– (aq)
what really exists?
what really exists is H3O+, not H+. If you see an equation like this shortcut, just know that really you should add a water molecule to the left and H+ should be H3O+ on the right.
Bronsted-Lowrey Definition: Acids are proton ____________.
donors
Bronsted-Lowrey Definition: Bases are proton ___________.
acceptors
Lewis Definition: Acids are electron pair ___________.
acceptors
Lewis Definition: Bases are electron pair ___________.
donors
A strong acid ionizes _____________ in water to create hydronium ion.
completely
A weak acid ionizes ______________ in water to create hydronium ion.
only partially
Notice how we used a one-way arrow for the ________________, indicating we expect that reaction to go essentially to ____________, but we used equilibrium arrows for the _______________, indicating that we expect the equilibrium mixture to be ______________________.
strong acid, completion
weak acid, a mix of reactants and products.
strong bases
LiOH
NaOH
KOH
RbOH
CsOH
Ca(OH)2
Sr(OH)2
Ba(OH)2
strong acids
HCl
HBr
HI
HClO4
HClO3
H2SO4
HNO3
Binary Acid:
Contains H plus one other element
Example: HCl (aq)
Organic (carboxylic) Acid:
Contain carboxyl group (-COOH)
Example: acetic acid, CH3COOH (aq)
Note that for this molecule, only the H that is part of the -COOH group is considered acidic. That is, only that proton is likely to be donated. The C-H bonds are expected to stay intact. Hence, this molecule would have one acidic hydrogen.
Ternary Acid (Oxoacid):
Contains three elements, with H attached to oxygen atom(s)
Examples: Nitrous, HNO2 (aq); nitric, HNO3 (aq)
Naming Binary Acids
HX, “hydro(X)ic acid”
Examples: HCl is hydrochloric acid; HF is hydrofluoric acid
Naming Ternary Acids: Polyatomic ions ending with “-ate” shift to “_______ acid”
-ic
Example: HNO3 is nitric acid.
Naming Ternary Acids: Polyatomic ions ending with “-ite” shift to “_________ acid”
-ous
Example: HNO2 is nitrous acid.
Monoprotic acids have _________________.
one acidic proton
Examples: HCl, HNO3
Polyprotic acids have _____________________.
more than one acidic proton
Diprotic:
has two acidic protons.
Example: sulfuric acid, H2SO4
Triprotic:
has three acidic protons
Example: phosphoric acid, H3PO4
H3PO4 would be classified as a ______________ and would be named _________________.
ternary acid, phosphoric acid
HBr is a _________________ acid and would be named _________________
binary, hydrobromic acid
It turns out that water is ______________, meaning it can accept or donate a proton. It can behave as an acid or a base.
amphiprotic
ACIDIC solution concentration:
[H+] > [OH-]
NEUTRAL solution concentration:
[H+] = [OH-]
BASIC solution concentration:
[H+] < [OH-]
the general form of “neutralization reactions”:
Acid + Base → Salt + Water
The point at which we have perfect stoichiometric ratios of the acid and base (the point where we have used up all of the acid and all of the base, with no excess of either) is called the ______________ point
equivalence
An ________________ is a substance that changes color based on the pH of the solution.
acid/base indicator
(not the cause of the changes of the pH)
The equivalence point is the point when _____________________. The end point is the point when __________________.
stoichiometric amounts of acid and base have reacted, the indicator changes color
For an acid base indicator to work well for your titration, it should change color
at a pH near the equivalence point pH
When we have an acid reacting with water, we give the equilibrium constant a special symbol:
Ka
When you dissolve 1 mole of HBr in enough water to make 1 L solution, you expect the resulting solution to have ___________. When you dissolve 1 mole of HNO2 in enough water to make 1 L solution, you expect the resulting solution to have _____________.
[H+] = 1 M, [H+] <1 M
Now think about the reverse reaction. If the reaction was moving in reverse, H3O+ goes to H2O, meaning it is donating a proton and hence acting as an __________. F- goes to HF, accepting a proton and hence acting as an __________.
H2O (l) + HF (aq) ⇌ H3O+ (aq) + F– (aq)
acid, base
H2O (l) + HF (aq) ⇌ H3O+ (aq) + F– (aq)
Base Acid Acid Base
A conjugate acid-base pair always consists of two molecules (or ions) that differ…
by one proton
An acidic salt is a salt that, when dissolved in water, produces a solution with a pH_______. It does this because there is a weak acid “hidden” in the salt formula.
pH<7
A basic salt is a salt that, when dissolved in water, produces a solution with a pH_________. It does this because there is a weak base “hidden” in the salt formula.
pH>7.
You dissolve a salt in water and measure the pH of the resulting solution. If the pH is 3.4, you know that the salt was a(n)
acidic salt
R: The top line is the _________ itself.
I: The next line is the ________ concentration, moles, or pressure.
C: The third line is the ___________, the amount that reacts or forms in order to reach equilibrium.
E: The final line is the actual ___________ amounts for each species.
Reaction, Initial, Change, Equilibrium
A higher Ka means that equilibrium lies more towards the ____________.
products
The protonated version will be the ________ and the deprotonated version will be the _________.
acid, base
While most weak acids and bases ionize very little, that small amount of ionization can still have a big effect on the _________ of the solution.
pH
Our expectation of the neutralization reaction going to completion is true whether our acids and bases…
are strong or weak
Classify NaCl as a neutral, acidic, or basic salt.
neutral
The parent acids and bases of NaCl (HCl and NaOH) are both strong.
Classify KCH3COO as a neutral, acidic, or basic salt.
basic
The acetate ion will act as a weak base.
Classify NH4Cl as a neutral, acidic, or basic salt.
acidic
The ammonium ion (NH4+) is the conjugate acid of ammonia (NH3).
hydronium ion
H3O+
hydroxide ion
OH-
LiOH
Lithium hydroxide
Lithium hydroxide
LiOH
LiOH is not as ____________ as the other strong bases
soluble
CsOH
Caesium hydroxide
Caesium hydroxide
CsOH