Analytical Chemistry

Question 1

It is a branch of chemistry involved with the analysis of a chemical substance.

Answer 1

Analytical Chemistry

Question 2

It establishes the chemical identity of the species in a sample.

Answer 2

Qualitative Analysis

Question 3

It determines the relative amounts of these species, or analytes, in numerical terms.

Answer 3

Quantitative Analysis

Question 4

Determination of mass of the analyte or some compound chemically related to it.

Answer 4

Gravimetric Methods

Question 5

Measurement of the volume of a solution containing sufficient reagent to react completely with the analyte.

Answer 5

Volumetric Methods

Question 6

Measurement of electrical properties (potential, current, resistance, quantity of electric charge, etc.), emission of radiation by analytes, etc.

Answer 6

Instrumental Methods

Question 7

A general expression for an amount of solute in a given amount of material.

Answer 7

Concentration

Question 8

Molarity (M)

Answer 8

amount of solute (mol) / volume of solution (L)

Question 9

molality (m)

Answer 9

amount of solute (mol) / mass of solvent (kg)

Question 10

Allows for simplified calculations involved with certain types of problems

Answer 10

Normality

Question 11

Based on measuring the amount of a substance required to react with an analyte completely.

Answer 11

Normality

Question 12

The reaction ratio still must be taken into account, but it is done by combining it with the molarity to produce a new unit of concentration called

Answer 12

“normal”

Question 13

Normality (N)

Answer 13

amount of solute (eq) / volume solution (L)

Normality = Molarity × h

Question 14

h = number of electrons lost or gained in the reaction

Answer 14

Redox Reactions

Question 15

h = number of participating H+ or OH− ions

Answer 15

Neutralization Reactions

Question 16

Water, as an amphiprotic solvent, undergoes

Answer 16

self-ionization or autoprotolysis

Question 17

Strong acids and bases ionize completely in

Answer 17

water

Question 18

Weak acids and bases ionize only partially in

Answer 18

water

Question 19

extent of ionization depends on the dissociation constants, which are

Answer 19

equilibrium constants

Question 20

Mixtures of weak acids or bases and their conjugate.

Answer 20

pH Buffers

Question 21

Have the ability to resist changes in pH upon dilution or addition of small amounts of acid or base.

Answer 21

pH Buffers

Question 22

Henderson-Hasselbalch Equation:

Answer 22

pH = pKa - log [acid]/[base]

Question 23

the quantity of strong acid or strong base needed to cause 1L of the buffer to undergo a pH change of 1.

Answer 23

Buffer capacity

Question 24

The buffer capacity increases as the concentration ratio approaches

Answer 24

1

Question 25

A solution is basic if:

Answer 25

[OH-] > [H+]

Question 26

Water at room temperature usually has a slightly acidic pH. This is largely attributed to what compound(s)?

Answer 26

Carbonic Acid

Question 27

When benzoic acid dissolves in water, it partially reacts with water and ionizes to form benzoate and hydronium ions. In this reaction, what is the conjugate acid?

Answer 27

Hydronium Ions

Question 28

Define a salt in terms of acid and base.

Answer 28

A salt is a compound (other than water) produced by the reaction of an acid and a base.

Question 29

When a can of soda is opened and CO2 is released to the atmosphere, what is the resultant pH of the soda?

Answer 29

Increases

Question 30

Which of the following pairs will form a buffer solution in the course of a titration?

Answer 30

Acetic acid, sodium hydroxide

Question 31

Buffer capacity is maximum when:

Answer 31

pH = pKa

Question 32

Which of the following acids would be most suitable for preparing a buffer of pH 3.1?

Answer 32

Sulfanilic acid, pKa = 3.232

Question 33

Determination of nitrogen based on the conversion of organic nitrogen to ammonia, which is then separated by distillation and determined by titration.

Answer 33

Kjeldahl Method

Question 34

Bases that can be titrated with a strong acid such as HCl.

Answer 34

Carbonate, bicarbonate, and hydroxide ions

Question 35

There are 5 possible sample compositions:

Answer 35

Na2CO3 alone, NaOH alone, NaHCO3 alone, Na2CO3+NaOH, and Na2CO3+NaHCO3.

Question 36

Titrations based on reactions that produce sparingly soluble substances (precipitates).

Answer 36

Precipitation Titrations

Question 37

Among the oldest titrations known, but are limited in scope because it is sometimes non-stoichiometric, has a slow reaction rate, and has issues of co-precipitation.

Answer 37

Precipitation Titrations

Question 38

Only procedures using silver ion (Ag+, argentometric titrations) as the titrant or analyte have remained competitive with newer analytical methods.

Answer 38

Precipitation Titrations

Question 39

Analyte: Cl-, Br-, CN- Titrant: AgNO3 (Ag+) Indicator: Na2CrO4 Titration reaction: Ag+ + Cl− ↔ AgCl (s) Indicator reaction: 2Ag+ + CrO2− ↔ Ag2CrO4 (s) Carried out at 6.510.3).

Answer 39

Mohr Method

Question 40

Analyte: Cl-, Br-, I-, SCN- Titrant: AgNO3 (Ag+) Indicator: Dichlorofluorescein (Cl-, Br-, I-, SCN-), eosin (Br-, I-, SCN-) Titration reaction: Ag+ + Cl− ↔ AgCl(s) Indicator reaction: AgCl ∙ Ag+ + DCF− ↔ AgCl ∙ Ag+ ∙ DCF−(s) Done with vigorous shaking to avoid coagulation. Addition of dextrin inhibits undesired coagulation of the AgCl.

Answer 40

Fajans Method

Question 41

Analyte: Cl-, Br-, I- Titrant: SCN- Indicator: FeSCN2+ (comes from ferric alum) Analyte reaction: Ag+ + Cl− ↔ AgCl(s) Titration reaction: Ag+ + SCN− ↔ AgSCN(s) Indicator reaction: Fe3+ + SCN− ↔ FeSCN2+(s) Nitrobenzene may be added to mask AgCl from reacting with SCN-

Answer 41

Volhard Method

Question 42

bonds where both bonding electrons come from one of the two atoms involved.

Answer 42

coordinate covalent bonds

Question 43

the molecule or ion containing the donor atom.

Answer 43

Ligand or coordinating agent

Question 44

the product resulting from the reaction between a metal ion and a ligand

Answer 44

Coordination compound or complex ion

Question 45

the number of pairs of electrons accepted by a particular metal ion (at least 4, often 6)

Answer 45

Coordination number

Question 46

can be classified according to how many donor atoms it contains (dentate)

Answer 46

Ligands

Question 47

When polydentate ligands coordinate with metal ions, ring structures known as ______ are formed.

Answer 47

chelates

Question 48

A hexadentate, containing 4 oxygen and 2 nitrogen donor atoms.

Answer 48

Ethylenediaminetetraacetic Acid (EDTA)

Question 49

EDTA

Answer 49

Ethylenediaminetetraacetic Acid

Question 50

can exist in a variety of protonated forms

Answer 50

tetraprotic acid

Question 51

Any or all of its protonated forms may react with a given metal to yield a metal

Answer 51

EDTA complex

Question 52

Theory of Complexation Indicators

Answer 52

M + In ↔ MIn MIn + Y ↔ MY + In