General Chemistry 10-12

Question 1

Compare and contrast 3 definitions of acid and bases (Arrhenius, Bronsted Lowry, and Lewis)

Answer 1

Arrhenius Acids - dissociates to form excess H+ in solution.
Arrhenius Bases - Dissociates to form excess OH- in solution

Bronsted Lowry Acid - H+ donor
Bronsted Lowry Base - H+ acceptor

Lewis Acid - Electron pair acceptor
Lewis Base - Electron pair donor

Question 2

Using Arrhenius naming trends, predict the acid formula and name for the following anions:
1. MnO4-
2. Titanate (TiO^2,3-)
3. I-
4. IO4-

Answer 2

1. HMnO4 (Permanganic acid)
2. H2TiO3 (Titanic acid)
3. HI (Hydroiodic acid)
4. HIO4 (Periodic Acid)

Question 3

What is an amphoteric species?

Answer 3

An atmospheric species can act as an acid or base.

Question 4

If a compound has a Ka value much greater than water, what does it mean about its behavior in solution?

How does this compare with a solution that only has a slightly higher Ka than water.

Answer 4

High Ka indicates a strong acid which will dissociate completely in solution.

A slightly higher Ka than water means the acid is weak with minimal dissociation.

Question 5

If a compound has a Kb value much greater than water, what does it mean about its behavior in solution?

How does this compare with a solution that only has a slightly higher Kb than water.

Answer 5

High Kb indicates a strong base and will dissociate completely in solution.

A slightly higher Kb than water means it is a weak base with minimal dissociation.

Question 6

What is the mathematical relationship between Ka, Kb, and Kw.?

Answer 6

Ka*Kb = Kw

Question 7

What species are considered the equivalents for acids and bases, respectively?
1. Acids
2. Bases

Answer 7

Acids use moles of H+ as an equivalent. Bases use moles of OH- as an equivalent.

Question 8

What is the buffering region of a titration curve?

Answer 8

[HA]~ [A-] and is the flattest portion of the titration curve. Is resistant to changes in the pH.

Question 9

What is the half-equivalence point of a titration curve?

Answer 9

Center of buffering region where [HA]=[A-].

Question 10

What is the equivalence point of a titration curve?

Answer 10

The steepest point of the titration curve and occurs when the equivalents of acid present equal the equivalence of base added (or vice versa)

Question 11

What is the endpoint of a titration curve?

Answer 11

The pH at which an indicator turns its final color.

Question 12

What is the purpose of a buffer solution?

Answer 12

Buffer solution is designed to resist changes in pH and has optimal buffering capacity within 1 pH point from its pKa.