Acids and Bases Flashcards
Arrhenius base
species that produces OH- in aqueous solution (hydroxide ions)
Arrhenius acid
species that produces H+ (hydrogen ions) in aqueous solution
An Arrhenius base can react with an Arrhenius acid in a/an ___________________ reaction.
neutralization
What is a neutralization reaction?
acid + base –> water + salt
Bronsted-Lowry acid
species that produces H+
True or False: Bronsted-Lowry bases and acids are the same as Arrhenius bases and acids.
FALSE: Bronsted-Lowry ACIDS are the SAME as Arrhenius ACIDS (species that produces H+)…but Bronsted-Lowry BASES are different from Arrhenius BASES.
Bronsted-Lowry Base
species that accepts H+
When a Bronsted-Lowry acid _______ a proton, it forms a conjugate base.
When a Bronsted-Lowry base _______ a proton, it forms a conjugate acid.
acid LOSES proton
base GAINS proton
Lewis acid
electron-pair acceptor
hint: lewis Acid = electron pair Acceptor
Lewis base
electron-pair donor
A Lewis acid is a/an:
a) electrophile
b) nucleophile
a) electrophile
hint: lewis Acid = electron pair Acceptor
A Lewis base is a/an:
a) electrophile
b) nucleophile
b) nucleophile
Which species is fundamental to understanding MCAT OCHEM?
a) Arrhenius
b) Bronsted-Lowry
c) Lewis
c) Lewis
True or False: a given species cannot have multiple classifications (Arrhenius, Bronsted Lowry, Lewis).
FALSE
List the strong acids (7).
HI (hydroiodic acid) HBr (hydrobromic acid) HCl (hydrochloric acid) HNO3 (nitric acid) HClO4 (perchloric acid) HClO3 (chloric acid) H2SO4 (sulfuric acid)
List the strong bases (7).
NaOH (sodium hydroxide) KOH (potassium hydroxide) NH2- (amide ion) H- (hydride ion) Ca(OH)2 (calcium hydroxide) Na2O (sodium oxide) CaO (calcium oxide)
What does the term “pH” refer to?
“potential of the hydrogen ion”
how is pH defined in terms of the proton concentration? (provide equation)
pH = -log[H3O+]
hint: p = -log[whatever]
How is pOH defined in terms of the hydroxide ion concentration? (provide equation)
pOH = -log[OH-]
hint: p = -log[whatever]
pH + pOH = ?
pH + pOH = pKw = 14 (at room temperature)
Calculate the following pH/pOH:
- log[1M] = ?
- log[1 x 10^-1 M] = ?
- log[1 x 10^-2 M] = ?
- log[1 x 10^-13 M] = ?
- log[1 x 10^-14 M] = ?
- log[1M] = 0
- log[1 x 10^-1 M] = 1
- log[1 x 10^-2 M] = 2
- log[1 x 10^-13 M] = 13
- log[1 x 10^-14 M] = 14
Calculate the following:
\+log(1) = ? \+log(3.2) = ? \+log(10) = ?
\+log(1) = 0 \+log(3.2) = 0.5 \+log(10) = 1
What is the pH of an aqueous solution of HCl with an initial concentration of 3.2 x 10^-5 M?
pH = -log(3.2 10^-5 M)
-log(10^-5M) = 5 \+log(3.2) = 0.5
pH = 5 - 0.5 =4.5
NOTE: SUBTRACT log of the mantissa
given the reaction below, what is the formula for the equilibrium constant (Kc)?
aA + bB –>/<– cC + dD
Kc = ( [C]^c [D]^d ) / ( [A]^a [B]^b )
Changes in which of the following influence(s) the equilibrium constant? Select all that apply:
a) volume
b) pressure
c) temperature
d) catalyst
c) temperature
TRUE OR FALSE: do NOT include pure liquids and gasses in the equilibrium constant calculation
TRUE
What does amphoteric mean?
can act as both and acid and a base
TRUE or FALSE: water is amphoteric
TRUE
What is the equilibrium equation for the self-ionization/autoionization of water?
H2O (acid) + H2O (base) –>/<– HO- (conjugate base) + H3O+ (conjugate acid)
What is the equilibrium constant for the self-ionization of water?
Kw = [H3O+][OH-] = 1.00 x 10^-14 ….at 25C and 1 atm
note: [H3O+] = [OH-] = 1.00 x 10^-7
Ka x Kb = ?
Ka x Kb = Kw = 10^-14
If Ka of a weak acid is greater than 10^-7 (e.g. 10^-6), its conjugate base will be __________.
a) stronger
b) weaker
hint: consider the value of Ka x Kb (or Kw)
b) weaker
If Ka of a weak acid is less than 10^-7 (e.g. 10^-8), its conjugate base will be __________.
a) stronger
b) weaker
hint: consider the value of Ka x Kb (or Kw)
a) stronger
What is the relationship between pKa and pKb? provide a formula/equation.
pKa + pKb = pKw = 14
acid strength ___________ with an increase in Ka.
a) increases
b) decreases
a) increases
acid strength ___________ with an increase in pKa.
a) increases
b) decreases
b) decreases
base strength ___________ with an increase in Ka.
a) increases
b) decreases
b) decreases
base strength ___________ with an increase in pKa.
a) increases
b) decreases
a) increases
provide the products:
strong acid + strong base –>
water + neutral ions
provide the products:
strong acid + weak base –>
water + acidic cation + neutral anion
provide the products:
weak acid + strong base
water + neutral cation + basic anion
provide the products:
weak acid + weak base
water + acidic cation + basic anion
As atomic radius increases, acid strength and stability of conjugate base ____________.
a) increase
b) decrease
a) increase
TRUE or FALSE: Acid strength increases to the right and down the periodic table (opposite of Zeff).
FALSE: SAME as Zeff
Resonance ______________ conjugate bases.
a) stabilizes
b) destabilizes
a) stabilizes
TRUE or FALSE: electronegativity increases with acid strength.
TRUE
TRUE or FALSE: an increase in induction (EWG) causes a decrease in acidity.
FALSE: acidity increases with induction
TRUE or FALSE: pKa increases as distance between the acidic proton and the electronegative atom increases.
TRUE
What is a zwitterion?
ion that can be protonated or deprotonated
For polyprotic acids, acid dissociation _____________ with sequential deprotonation.
a) increases
b) decreases
b) decreases
At the equivalence/stoichiometric point (pH 7), number of moles of acid are _______________ number of moles of base.
a) greater than
b) less than
c) equal to
c) equal to
What is the name of the chemical used to visualize the equivalence point?
indicator
TRUE or FALSE: An indicator is usually a strong acid or strong base; whose conjugate form is a different colour.
FALSE: an indicator is usually a WEAK acid or base
When does the indicator change colour?
at the end point
TRUE or FALSE: A correct indicator will change colour at a pH that is far from the equivalence point, so that you can distinguish the end point from the equivalence point.
FALSE: A correct indicator will change colour at a pH that is very CLOSE tot he equivalence point.
ADD QUESTION ABOUT TITRATION CURVES
