Acids and Bases

Question 1

(Acids and Bases) Brônsted-Lowery Reactions

Answer 1

HA + B ⇌ BH⁺ + A⁻

HA : Acid
B : Base
BH⁺ : Conjugate acid of B
A⁻: Conjugate base of HA

Question 2

(Acids and Bases) Acids ______ protons and bases ______ protons.

Answer 2

donate, accept

Question 3

(Acids and Bases) Strong acids completely dissociate in water. Equilibrium lies…

Answer 3

far to the right, and thus when writing a chemical equation, use a one way arrow (→).

Question 4

(Acids and Bases) Weak acids partially dissociate in water. Equilibrium lies…

Answer 4

to the left or roughly in the middle, and thus when writing a chemical equation, use a two way arrow (⇌).

Question 5

(Acids and Bases) The “Big Six” Strong Acids

Answer 5

HClO₄ (perchloric acid)

HCl (hydrochloride acid)

HI (hydroiodic acid)

HNO₃ (nitric acid)

HBr (hydrobromic acid)

H₂SO₄ (sulfuric acid)

Question 6

(Acids and Bases) Strong Bases

Answer 6

Soluble compounds containing the hydroxide ion.

Possible cations:
• All group 1A cations (K⁺, Na⁺, Li⁺, etc.)
• Ca²⁺, Sr²⁺, Ba²⁺

Question 7

(Acids and Bases) Strong acids always have _________ conjugate bases.

Answer 7

very weak

Question 8

(Acids and Bases) Very weak acids have ___________ conjugate bases.

Answer 8

very strong

Question 9

(Acids and Bases) The stronger base always accepts the ____ protons in an acid/base reaction.

Answer 9

most

Question 10

(Trends) Binary Acid Strengths; acid strength increases—base strength of conjugate base decreases as…

Answer 10

anion radius increases.

Question 11

(Acids and Bases) Oxoacid Types

Answer 11

HOY:

H-O-Y

HYOₓ:

H-O-Y-O
|
O

Question 12

(Trends) HOY Oxoacid Strengths; acid strength and Kₐ increase as…

Answer 12

electronegativity of Y increases.

Question 13

(Trends) HYOₓ Oxoacid Strengths; acid strength and Kₐ increase as…

Answer 13

oxygens are added to Y.

Question 14

(Acids and Bases) Carboxylic Acids

Answer 14

Weak organic acids that take on the form:

R-C-O-H
||
O

R—pretty much anything.

Question 15

(Trends) Carboxylic Acid Strengths; acid strength increases as…

Answer 15

electronegativity of the elements that make up “R” increases.

Question 16

(Acids and Bases) K Value of Water

Answer 16

Kw = 1.0*10^-14

Question 17

(Acids and Bases) [H₃O⁺] > [OH⁻];

Answer 17

Solution is acidic.

Question 18

(Acids and Bases) [H₃O⁺] < [OH⁻];

Answer 18

Solution is basic.

Question 19

(Acids and Bases) [H₃O⁺] = [OH⁻];

Answer 19

Solution is neutral.

Question 20

(Acids and Bases) The pH Formula(s)

Answer 20

[H⁺]=10^(-pH)

Thus:

pH=-log[H⁺]
or
pH=-log[H₃O⁺]

Question 21

(Acids and Bases) The pH Scale

Answer 21

Basic

14
13
12
11
10
9
8
7
6
5
4
3
2
1

Acidic

Question 22

(Problem Solving) When calculating pH for strong acids, we assume 100% dissociation.

Answer 22

Example: Find the pH of a 2.5 M HCl solution.

pH=-log[H⁺]
pH=-log[2.5]
pH=-0.40

Number of significant figures in the concentration is equal to the number of decimal places given to the pH.

Question 23

(Acids and Bases) The pOH Formula

Answer 23

pOH=-log[OH⁻]

Question 24

(Acids and Bases) The stronger the acid, the ______ the Kₐ value.

Answer 24

larger

Question 25

(Acids and Bases) The stronger the base, the ______ the Kb value

Answer 25

larger

Question 26

(Acids and Bases) pK Equations

Answer 26

pKa=-log(Ka)
Ka=10^(-pKa)

pKb=-log(Kb)
Kb=10^(-pKb)

Question 27

(Trends) The stronger the acid, the _______ the pKa.

Answer 27

smaller

Question 28

(Trends) The stronger the base, the _______ the pKb.

Answer 28

smaller

Question 29

(Acids and Bases) Kw Equations

Answer 29

Kw=[H₃O⁺][OH⁻]

Kw=Ka*Kb

-logKw=-logKa*-logKb

pKw=pKa+pKb=14

pKw=pOH+pH=14

Question 30

(Acids and Bases) pKa > pKb

Answer 30

The solution is acidic.

Question 31

(Acids and Bases) pKa < pKb

Answer 31

The solution is basic.

Question 32

(Acids and Bases) pKa = pKb

Answer 32

The solution is neutral.