4A Acids and Bases

Question 1

When is solubility high in water and when is it low

Answer 1

High: Polar
Low: Nonpolar

Question 2

What causes the dissolving of ions in an ionic compound in water

Answer 2

Dissolving forces of water and stronger than binding forces in an ionic compound

Question 3

What is the Arrhenius (classic) definition of acids and bases

Answer 3

Acid: A subtsnace that propduces H+ (or H3O+) in water
Base: A substance that produces OH- in water

Question 4

What is the Bronstead-Lowry definition of acids and bases

Answer 4

Acid: A proton donor (H+)
Base: Proton acceptor

Question 5

What is the Lewis definition of an acid and base

When is the definition useful

Answer 5

Acid: A substance that can accept a pair of electrons
Base: A substance that can donate a pair of electrons

Useful for describing reactions in non-aqueous environments

Question 6

What is meant by the autoionization of water

Answer 6

A process that* usually* involves two H2O molecules and acts both as a H+ donor and acceptor

Question 7

What is Kw known as it’s definition

Answer 7

Ion-Product constant (Kw) is the product of the moalr concentrations of H+ and OH- at a particular temperature

Question 8

What is the realtionship between bond strength and acid strength

Answer 8

The stronger the bond, the weaker the acid

Question 9

If a molecules has 3 atoms (O, H, Z). The O-H bond will be more polar and easier to break if Z is:

Answer 9

1. Z is very electronegative
2. Z is in a high oxidation state

Question 10

1. What are oxoacids

Answer 10

Acids that contains an oxygen

Question 11

If an oxoacid has different central atoms Z) that are from the same group and have the same oxidation number, what increases acid strength

Answer 11

Acid strength increases with increasing electronegativity of Z
HClO3>HBro3

Question 12

If an oxoacid has the same central atom (Z) but different numbers of attached groups, what increases acid strength

Answer 12

Increasing the oxidation number of Z increases

Question 13

What is a strong acid are what are the 7 strong acids

Answer 13

When dissolved in water, a strong acid almost completely (100%) dissolves into H+ ions and anions
Hcl, HI, HBr, HClO4, HClO3, H2SO4, HNO3

Question 14

What is a weak acid

Answer 14

When dissolved in water, a weak acid only partially dissociates into H+ ions and anions

Question 15

The stronger the acid, the ____ its conjugate base

Answer 15

WEAKER

Question 16

1. What is Ka known as? What does a small and large Ka represent
2. What is kb known as? Small and large represent

Answer 16

1. Ka is called acid ionization constant. Ka is small for weak acids. Approaches infinity for strong acids
2. Kb is the base ionization constant. Small Kb is weak base, large Kb is strong base

Question 17

How do you find pKa and pKb

The stronger the acid, the _____ pKa

Answer 17

pkA=-log(Ka)
pkB=-log(Kb)

SMALLER pKA

Question 18

What does pKa+pKb=

Is pKa=pH

Answer 18

14

NO