Chapter 19 Vocab

Question 1

acid dissociation constant (Ka)

Answer 1

the ratio of the concentration of the dissociated form of an acid to the undissociated form; stronger acids have larger Ka values than weaker acids

Question 2

acidic solution

Answer 2

any solution in which the hydrogen-ion concentration is greater than the hydroxide-ion concentration

Question 3

alkaline solution

Answer 3

a basic solution

Question 4

amphoteric

Answer 4

a substance that can act as both an acid and a base

Question 5

base dissociation constant (Kb)

Answer 5

the ratio of the concentration of the acid times the concentration of the hydroxide ion to the concentration of the base

Question 6

basic solution

Answer 6

any solution in which the hydroxide-ion concentration is greater than the hydrogen-ion concentration

Question 7

buffer

Answer 7

a solution in which the pH remains relatively constant when small amounts of acid or base are added; a buffer can be either a solution of a weak acid and the salt of a weak acid or a solution of a weak base with the salt of a weak base

Question 8

buffer capacity

Answer 8

a measure of the amount of acid or base that may be added to a buffer solution before a significant change in pH occurs

Question 9

conjugate acid

Answer 9

the particle formed when a base gains a hydrogen ion; NH4+ is the conjugate acid of the base NH3

Question 10

conjugate acid-base pair

Answer 10

two substances that are related by the loss or gain of a single hydrogen ion; ammonia (NH3) and the ammonium ion (NH4+) are a conjugate acid-base pair

Question 11

conjugate base

Answer 11

the particle that remains when an acid has donated a hydrogen ion; OH- is the conjugate base of the acid water

Question 12

diprotic acid

Answer 12

any acid that contains two ionizable protons (hydrogen ions); sulfuric acid (H2SO4) is a diprotic acid

Question 13

end point

Answer 13

the point in a titration at which the indicator changes color

Question 14

equivalence point

Answer 14

the point in a titration where the number of moles of hydrogen ions equals the number of moles of hydroxide ions

Question 15

hydronium ion (H3O+)

Answer 15

the positive ion formed when a water molecule gains a hydrogen ion

Question 16

ion-product constant for water (Kw)

Answer 16

the product of the concentrations of hydrogen ions and hydroxide ions in water; it is 1X10-14 at 25°C

Question 17

Lewis acid

Answer 17

any substance that can accept a pair of electrons to form a covalent bond

Question 18

Lewis base

Answer 18

any substance that can donate a pair of electrons to form a covalent bond

Question 19

monoprotic acids

Answer 19

any acid that contains one ionizable proton (hydrogen ion); nitric acid (HNO3) is a monoprotic acid

Question 20

neutral solution

Answer 20

an aqueous solution in which the concentrations of hydrogen and hydroxide ions are equal; it has a pH of 7.0

Question 21

neutralization reaction

Answer 21

a reaction in which an acid and a base react in an aqueous solution to produce a salt and water

Question 22

pH

Answer 22

a number used to denote the hydrogen-ion concentration, or acidity, of a solution; it is the negative logarithm of the hydrogen-ion concentration of a solution

Question 23

salt hydrolysis

Answer 23

a process in which the cations or anions of a dissociated salt accept hydrogen ions from water or donate hydrogen ions to water

Question 24

self-ionization

Answer 24

a term describing the reaction in which two water molecules react to produce ions

Question 25

standard solution

Answer 25

a solution of known concentration used in carrying out a titration

Question 26

strong acid

Answer 26

an acid that is completely (or almost completely) ionized in aqueous solution

Question 27

strong base

Answer 27

a base that completely dissociates into metal ions and hydroxide ions in aqueous solution

Question 28

titration

Answer 28

process used to determine the concentration of a solution (often an acid or base) in which a solution of known concentration (the standard) is added to a measured amount of the solution of unknown concentration until an indicator signals the end point

Question 29

triprotic acid

Answer 29

any acid that contains three ionizable protons (hydrogen ions); phosphoric acid (H3PO4) is a triprotic acid

Question 30

weak acid

Answer 30

an acid that is only slightly ionized in aqueous solution

Question 31

weak base

Answer 31

a base that reacts with water to form the hydroxide ion and the conjugate acid of the base