Book: Key Terms: 18

Question 1

acid-base indicator

Answer 1

Organic molecules whose colors depend on the acidity of the solution in which they are dissolved.

Question 2

acid-dissociation (acid-ionization) constant (K_a)

Answer 2

The equilibrium constant specifically for acid dissociation: K_a = [H3O+][A-] / [HA], for weak acid HA.

Question 3

adduct

Answer 3

The product of a Lewis acid-base reaction: a single species that contains a new covalent bond. A + B ⇌ A—B (adduct).

Question 4

Arrhenius acid-base definition

Answer 4

A definition of acids and bases that classifies these substances according to their formulas and behaviors in water: an acid is a substance with H in its formula that dissociates in water to yield a H3O+, while a base is a substance with OH in its formula that dissociates in water to yield OH-.

Question 5

autoionization

Answer 5

The equilibrium process by which water dissociates very slightly into H3O+ and OH-.

Question 6

base-dissociation (base-ionization) constant (K_b)

Answer 6

The equilibrium expression for the dissociation of base in water: K_a = [BH+][OH-] / [B] for base B.

Question 7

Bronsted-Lowry acid-base definition

Answer 7

A definition for acids and bases that describes acids as proton (p+ or H+) donors while bases are considered proton acceptors.

Question 8

conjugate acid-base pair

Answer 8

Any acid has a conjugate base, and vice versa for bases. For any conjugate acid-base pair, the conjugate base has one fewer H and one more negative charge than the acid, while the conjugate acid has one more H and one fewer negative charge than the base.

Question 9

hydronium ion, H3O+

Answer 9

The charge density of the proton is so strong that it attracts water molecules especially strong,y covalently bonding to one of the lone electron pairs of the water molecule’s O atom. The result is hydronium, or H3O+. [H3O+] is equivalent to [H+].

Question 10

ion-product constant for water (K_w)

Answer 10

To describe the autoionization of water, K_w is constructed to reflect the dissociation of water molecules into H3O+ and OH-: K_w = [H3O+][OH-], but since the concentration of pure water is essentially constant, K_w is also essentially constant at K_w = 1.0×10^-14, and K_w at 25 C always takes this value.

Question 11

leveling effect

Answer 11

Water exerts this effect on any strong acid or base by reacting with it to form the products of the autoionization of water. Acting as a base, water levels the strength of all strong acids by making them appear equally strong, and acting as an acid, it levels the strength of all strong bases.

Question 12

Lewis acid-base definition

Answer 12

A definition of acids and bases which holds that bases are any species that donate electron pairs to form bonds, while acids are any species that accept electron pairs to form bonds.

Question 13

neutralization

Answer 13

In the Arrhenius sense, neutralization occurs when H+ from an acid and the OH- from a base react to form H2O.

Question 14

pH

Answer 14

pH = - log [H3O+]

Question 15

polyprotic acid

Answer 15

Acids with more than one ionizable proton.

Question 16

proton acceptor

Answer 16

Bases according to the Bronsted-Lowry definition; any species that accepts an H+ ion.

Question 17

proton donor

Answer 17

Acids according to the Bronsted-Lowry definition; any species that donates an H+ ion.