AQUEOUS SOLUTIONS AND CHEMICAL EQUILIBRIA

Question 1

substances that have a natural positive or negative electrical charge when dissolved in water

Answer 1

Electrolytes

Question 2

Ionized completely in a solvent

Answer 2

Strong Electrolytes

Question 3

Ionized partially on solvent

Answer 3

Weak Electrolytes

Question 4

produced in the reaction of an acid with a base - Examples include NaCl, Na2SO4, and NaOOCCH3 (sodium acetate)

Answer 4

Salt

Question 5

acid is a proton donor, and a base is a proton acceptor - For a molecule to behave as an acid, it must encounter a proton acceptor (or base). Likewise, a molecule that can accept a proton behaves as a base if it encounters an acid.

Answer 5

Brønsted-Lowry Theory

Question 6

formed when an acid loses a proton. For example, acetate ion is the conjugate base of acetic acid

Answer 6

Conjugate Base

Question 7

formed when a base accepts a proton

Answer 7

Conjugate Acid

Question 8

is the hydrated proton formed when water reacts with an acid

Answer 8

Hydronium Ions

Question 9

species that have both acidic and basic properties

Answer 9

Amphiprotic Species

Question 10

are an important class of amphiprotic compounds that contain both a weak acid and a weak base functional group

Answer 10

simple amino acids

Question 11

a species that has both a positive and a negative charge

Answer 11

zwitterion

Question 12

is the classic example of an amphiprotic solvent, that can act either as an acid or as a base depending on the solute.

Answer 12

Water

Question 13

Other Common Amphiprotic Solvents

Answer 13

methanol, ethanol, and anhydrous acetic acid

Question 14

(also called autoionization) is the spontaneous reaction of molecules of a substance to give a pair of ion

Answer 14

Autoprotolysis

Question 15

reaction with the solvent is sufficiently complete that no undissociated solute molecules are left in aqueous solution

Answer 15

Strong Acids

Question 16

react incompletely with water to give solutions containing significant quantities of both the parent acid and its conjugate base

Answer 16

Weak Acids

Question 17

various acids dissociate to different degrees and have different strengths

Answer 17

Differentiating Solvent

Question 18

everal acids are completely dissociated and show the same strength

Answer 18

Leveling Solvent

Question 19

the ratio of concentrations of reactants and products is constant

Answer 19

Chemical Equilibrium

Question 20

are algebraic equations that describe the concentration relationships among reactants and products at equilibrium

Answer 20

Equilibrium-constant Expressions

Question 21

states that the position of an equilibrium always shifts in such a direction as to relieve a stress that is applied to the system
an increase in temperature of a system alters the concentration relationship in the direction that tends to absorb heat, and an increase in pressure favors those participants that occupy a smaller total volume

Answer 21

Le Châtelier’s Principle

Question 22

a shift in the position of an equilibrium caused by adding one of the reactants or products to a system

Answer 22

Mass-action Effect

Question 23

is a branch of chemistry that concerns the flow of heat and energy in chemical reactions. The position of a chemical equilibrium is related to these energy changes

Answer 23

Chemical Thermodynamics

Question 24

resists changes in pH when it is diluted or when acids or bases are added to it

Answer 24

Buffer Solution

Question 25

The analyte is separated from a solution of the sample as a precipitate and is converted to a compound of known composition that can be weighed

Answer 25

Precipitation Gravimetry

Question 26

the analyte is separated from other constituents of a sample by converting it to a gas of known chemical composition

Answer 26

Volatilization Gravimetry

Question 27

the analyte is separated by deposition on an electrode by an electrical current The mass of this product then provides a measure of the analyte concentration

Answer 27

Electrogravimetry

Question 28

the mass of a reagent of known concentration required to react completely with the analyte provides the information needed to determine the analyte concentration

Answer 28

Gravimetric Titrimetry

Question 29

uses a mass spectrometer to separate the gaseous ions formed from the elements making up a sample of matter

Answer 29

Atomic Mass Spectroscopy

Question 30

a stable phase showing little tendency to aggregate and separate from the aqueous phase

Answer 30

Colloidal Suspensions

Question 31

composed of particles having large diameters about a tenth of a millimeter or greater

Answer 31

Crystalline Suspension

Question 32

is the effect of light scattering in colloidal dispersion while showing no light in a true solution This effect is used to determine whether a mixture is a true solution or a colloid

Answer 32

Tyndall Effect

Question 33

the ratio of the difference of the concentration of the reactants and the solubility of the precipitate to the solubility of the precipitate. Supersaturation ratio is defined as the supply rate of solute Q based on the growth rate in a quasisteady state

Answer 33

Relative Super Saturation

Question 34

the initial process of the formation of a crystal. The crystals may form from solutions, liquids or from vapo

Answer 34

Nucleation

Question 35

the process of increasing the size of a pre-existing crystal structure

Answer 35

Particle growth or crystal growth

Question 36

Particle Growth or Crystal Growth in Three Stages

Answer 36

Nucleation Coalescent Coagulation Agglomeration

Question 37

is an unstable solution that contains a higher solute concentration than a saturated solution. As excess solute precipitates with time, supersaturation decreases to zero

Answer 37

Supersaturated Solution

Question 38

is a process in which a substance (gas, liquid, or solid) is held on the surface of a solid A

Answer 38

Adsorption

Question 39

is retention of a substance within the pores of a solid

Answer 39

Absorption

Question 40

Consist mainly of adsorbed ions

Answer 40

Primary Adsorption Layer

Question 41

which contains sufficient excess of negative ions to just balance the charge on the surface of the particle

Answer 41

Counter – ion Layer

Question 42

is a process by which a coagulated colloid returns to its dispersed state

Answer 42

Peptization

Question 43

is a process in which a precipitate is heated in the solution from which it was formed (the mother liquor) and allowed to stand in contact with the solution

Answer 43

Digestion

Question 44

is the solution from which a precipitate was formed

Answer 44

Mother Liquor

Question 45

is a process in which normally soluble compounds are carried out of solution by a precipitate

Answer 45

Coprecipitation

Question 46

Four Types of Coprecipitation

Answer 46

1. Surface Adsorption 2. Mixed – crystal Formation 3. Occlusion 4. Mechanical Entrapment

Question 47

common source of coprecipitation and is likely to cause significant contamination of precipitates with large specific surface areas that is coagulated colloids

Answer 47

Surface Adsorption

Question 48

a drastic but effective way to minimize the effects of adsorption

Answer 48

Reprecipitation

Question 49

is a type of coprecipitation in which a contaminant ion replaces an ion in the lattice of a crystal

Answer 49

Mixed-Crystal Formation

Question 50

- is a type of coprecipitation in which a compound is trapped within a pocket formed during rapid crystal growth

Answer 50

Occlusion

Question 51

occurs when crystals lie close together during growth

Answer 51

Mechanical Entrapment

Question 52

is a process in which a precipitate is formed by slow generation of a precipitating reagent homogeneously throughout a solution

Answer 52

Homogeneous precipitation

Question 53

typically form slightly soluble salts or hydrous oxides with the analyte

Answer 53

Inorganic Precipitating Agents

Question 54

loses electrons and is oxidized in a chemical reaction.

Answer 54

Reducing Agents

Question 55

chemical compound that binds tightly to metal ions compounds typically contain at least two

Answer 55

Chelating Agents

Question 56

cyclical metal-organic compounds in which the metal is a part of one or more five- or sixmembered rings.

Answer 56

Chelates

Question 57

Widely Used Chelating Agents

Answer 57

8-Hydroxyquinoline (oxine) Dimethylglyoxime Sodium Tetraphenylborate

Question 58

vary widely from cation to cation and are pH dependent because 8-hydroxyquinoline is always deprotonated during a chelation reaction.

Answer 58

8-Hydroxyquinoline (oxine)

Question 59

is an organic precipitating agent of unparalleled specificity

Answer 59

Dimethylglyoxime

Question 60

is an important example of an organic precipitating reagent that forms salt-like precipitates

Answer 60

Sodium Tetraphenylborate