CHEM 162 - ACIDS AND BASES TO
REVIEW EXAM QUESTIONS AND
ANSWERS
What is the Arrhenius definition of an acid? - Correct Answers -a molecular compound
that dissociates in water to generate H+/H3O+ ions (and the associated anions
What is the Arrhenius definition of a base? - Correct Answers -a compound(either ionic
or molecular) that generates OH-(hydroxide) ions when placed into water
What is the Bronsted-Lowery acid? - Correct Answers -proton (H+) donor
What is the Bronsted-Lowery base? - Correct Answers -proton (H+) acceptor
What is a proton donor? - Correct Answers -bronsted lowery acid
What is a proton acceptor? - Correct Answers -bronsted lowery base
What is a conjugate base? - Correct Answers -when an acid loses its H+, it becomes a
conjugate base
What is a conjugate acid? - Correct Answers -when a base gains one H+, it becomes a
conjugate acid
How do you quantify the strength of binary acids? - Correct Answers -NOTE that for
binary acids, electronegativity is the more important factor only when comparing acids
within the same period and NOT when comparing acids within the same group
What increases the acid strength of oxyacids? - Correct Answers -(1) electrnegativity of
Y - the more electrnegative the central atom of the oxyacid, the weaker the H-O bond
(2) more oyxgens bound to central chlorine = stronger acid
(3) the more chlorines adjacent to carboxlyic group, stronger the acid
Calculating pH for a single strong acid in water - Correct Answers -• calculate [H3O+]
from the complete dissociation of the acid
, • neglect the contribution of [H3O+] from the autoionization of water unless thestrong
acid is very dilute (≈ 10-5 M or less)
• for example: 1.0 M HCl(aq) vs. 1.0×10-6 M HCl(aq) vs. 1.0×10-10 M HCl(aq)
• use [H3O+] to calculate resulting pH of the solution
Calculating the pH for a mixture of two strong acids - Correct Answers -• calculate
moles of H3O+ separately from the complete dissociation of each acid and add to get
total moles of H3O+
• divide total moles of H3O+ by total volume of solution (in L) to get total [H3O+]
• use [H3O+]total to calculate resulting pH of the mixture
Calculating the pH for a single weak acid in water - Correct Answers -calculate [H3O+]
from the partial dissociation of the weak acid by using an ICEtable and the Ka of the
acid
• typically neglect the contribution of [H3O+] from the autoionization of water
• solve for the value of x using an equilibrium expression
• look to make the small-K approximation to make the calculations simpler
Calculate the pH of a 2.5 M HNO2 solution given that its Ka = 4.6×10-4. = 1.47
Calculating the pH for a mixture of two weak acids (with each component having aprox
the same concentration) - Correct Answers -the weak acid with the larger Ka value will
dictate the pH of the overall mixture(provided that the Ka of the stronger acid is larger
by a factor of at least severalhundred)
Common Weak Bases have ? - Correct Answers -NH2 at the end that accepts a
hydrogen to produce NH3 + OH-
NH3 is a - Correct Answers -weak base
NH4+ is a - Correct Answers -weak acid
What are ions that DO NOT impact the pH of a solution? - Correct Answers -1. anions
that are the conjugate bases of monoprotic strong acids
• Cl-, Br-, I-, NO3-, ClO4-2.
2. cations that are the counterions of strong bases
• Li+, Na+, K+, Rb+, Ca2+, Sr2+, Ba2+•
REVIEW EXAM QUESTIONS AND
ANSWERS
What is the Arrhenius definition of an acid? - Correct Answers -a molecular compound
that dissociates in water to generate H+/H3O+ ions (and the associated anions
What is the Arrhenius definition of a base? - Correct Answers -a compound(either ionic
or molecular) that generates OH-(hydroxide) ions when placed into water
What is the Bronsted-Lowery acid? - Correct Answers -proton (H+) donor
What is the Bronsted-Lowery base? - Correct Answers -proton (H+) acceptor
What is a proton donor? - Correct Answers -bronsted lowery acid
What is a proton acceptor? - Correct Answers -bronsted lowery base
What is a conjugate base? - Correct Answers -when an acid loses its H+, it becomes a
conjugate base
What is a conjugate acid? - Correct Answers -when a base gains one H+, it becomes a
conjugate acid
How do you quantify the strength of binary acids? - Correct Answers -NOTE that for
binary acids, electronegativity is the more important factor only when comparing acids
within the same period and NOT when comparing acids within the same group
What increases the acid strength of oxyacids? - Correct Answers -(1) electrnegativity of
Y - the more electrnegative the central atom of the oxyacid, the weaker the H-O bond
(2) more oyxgens bound to central chlorine = stronger acid
(3) the more chlorines adjacent to carboxlyic group, stronger the acid
Calculating pH for a single strong acid in water - Correct Answers -• calculate [H3O+]
from the complete dissociation of the acid
, • neglect the contribution of [H3O+] from the autoionization of water unless thestrong
acid is very dilute (≈ 10-5 M or less)
• for example: 1.0 M HCl(aq) vs. 1.0×10-6 M HCl(aq) vs. 1.0×10-10 M HCl(aq)
• use [H3O+] to calculate resulting pH of the solution
Calculating the pH for a mixture of two strong acids - Correct Answers -• calculate
moles of H3O+ separately from the complete dissociation of each acid and add to get
total moles of H3O+
• divide total moles of H3O+ by total volume of solution (in L) to get total [H3O+]
• use [H3O+]total to calculate resulting pH of the mixture
Calculating the pH for a single weak acid in water - Correct Answers -calculate [H3O+]
from the partial dissociation of the weak acid by using an ICEtable and the Ka of the
acid
• typically neglect the contribution of [H3O+] from the autoionization of water
• solve for the value of x using an equilibrium expression
• look to make the small-K approximation to make the calculations simpler
Calculate the pH of a 2.5 M HNO2 solution given that its Ka = 4.6×10-4. = 1.47
Calculating the pH for a mixture of two weak acids (with each component having aprox
the same concentration) - Correct Answers -the weak acid with the larger Ka value will
dictate the pH of the overall mixture(provided that the Ka of the stronger acid is larger
by a factor of at least severalhundred)
Common Weak Bases have ? - Correct Answers -NH2 at the end that accepts a
hydrogen to produce NH3 + OH-
NH3 is a - Correct Answers -weak base
NH4+ is a - Correct Answers -weak acid
What are ions that DO NOT impact the pH of a solution? - Correct Answers -1. anions
that are the conjugate bases of monoprotic strong acids
• Cl-, Br-, I-, NO3-, ClO4-2.
2. cations that are the counterions of strong bases
• Li+, Na+, K+, Rb+, Ca2+, Sr2+, Ba2+•
