Analytical Chemistry Chapter 2

Question 1

A standardized system of units that the scientist adopt

Answer 1

International System of Units (SI)

Question 2

SI is the acronym of the:

Answer 2

“Système international d’Unités”

Question 3

a non-SI unit of length that is widely used to express the wavelength of very short radiation such as x-rays.

Answer 3

Angstrom Unit (Å)

Question 4

How to determine the amount of chemical species?

Answer 4

Mass Measurement

Question 5

Name the Unit and Abbreviation

Mass
Length
Time
Temperature
Amount of substance
Electric current
Luminous density

Answer 5

kilogram - kg
Meter - m
Seconds - s
Kelvin - K
Mole - m
Ampere - A
Candela - cd

Question 6

The _________ is the SI unit for the amount of a chemical substance.

It is always associated with specific microscopic entities such as atoms, molecules,
ions, electrons, other particles, or specified groups of such particles as represented by a
chemical formula.

One mole contains exactly _______elementary entities
(atoms, molecules, ions, electrons, and so on)

6.02214076×10²³ is known as _________

When expressed in the unit mol⁻¹, this number is
called _______, which is often rounded to __________

Answer 6

mole (mol)

6.02214076×10²³

Avogadro’s constant

Avogadro’s number

6.022×10²³ mol⁻¹

Question 7

How do we calculate molar masses?

Answer 7

Summing the atomic masses of all the atoms appearing in a chemical formula

Question 8

The ________ of a substance is the mass in grams of 1 mole of that substance.

Answer 8

Molar Mass (M)

Question 9

______ is an
unchanging measure of the quantity of matter in an object.

_______ invariant measure of the amount of matter.

_______ is the force
of attraction between an object and its surroundings, principally Earth.

the force of gravitational attraction between that matter and earth.

Weight and mass are related by the familiar expression _________
where w is the _____,
m is its ______, and
g is the _________.

Answer 9

Mass

Weight

w=mg

weight of an object

mass

acceleration due to
gravity

Question 9

The distinction between mass and weight is often lost in common usage, and the process of comparing masses is usually called ______.

The objects of known mass as well as the results of weighing are frequently called______.

Always bear in mind, however, that analytical data are based on _____ rather than _______.

Usage of _____ is for the act of determining the mass of an object. Also, we often say ________
to mean the standard masses used in weighing.

Answer 9

weighing

weights

mass, weight

weights

Question 10

The masses for the elements listed in the table 2-1 (SI Base Units) are relative masses in terms of ______.

The ______ is defined as 1/12 the mass of a neutral 12C atom

Answer 10

unified atomic mass units (u) or daltons (Da)

dalton

Question 11

The ________ is 1/1000 of a mole, and the mass in grams of a millimole,
the millimolar mass (mM), is likewise 1/1000 of the molar mass.

1 mmol = 10^-3 mol
10^3 mmol = 1 mol

Answer 11

millimole

Question 12

There are four fundamental ways of expressing solution concentration

Answer 12

molar concentration percent concentration solution-diluent volume ratio
p-functions.

Question 13

The ________ of a solution of a solute species X is the number of moles of that species that is contained in 1 L of the solution (not 1 L of the solvent).

Answer 13

molar concentration of solution of a chemical species X

Question 14

symbolized by M, which has the dimensions of mol/L, or mol^-1.

Is also equal to the number of millimoles of solute per milliliter of solution.

Answer 14

Molar concentration or molarity

Question 15

If the number moles of solute is nx, and the volume of solution is V, the molar concentration is cx, what is the equation?

Equation when finding a number of moles.

Answer 15

cx=nx/V

Molarity =

M= no. mol solute/no L. solution

=no. mmol solute/no mL. solution

NA = CA x VA

Question 16

is the total number of moles of a solute,
regardless of its chemical state, in 1 L of solution. It describes how a
solution of a given concentration can
be prepared.

Answer 16

Molar analytical concentration

Question 17

Gives the total number of moles of a solute in 1 L of the solution or the total number of millimoles in 1 ml.

Specifies a recipe by which the solution can be prepared.

Total number of moles of a solute, regardless of its chemical state, in one liter of solution. It describes how a solution can be prepared.

Answer 17

Analytical Molarity

Question 18

Express the molar concentration of a particular species in a solution at equilibrium.

To determine the species molarity, it is necessary to know _________.

Molar concentration of a particular species in a solution at equilibrium.

Answer 18

Equilibrium Molarity

how the solute behaves when it is dissolved in a solvent

Question 19

In percent concentration what are the three common method:

the denominator in each of these expressions is the ____________ rather than mass or volume of solvent

Only __________ has the advantage of being temperature independent

Answer 19

mass or volume of solution

weight percent

Question 20

______is often used to express the concentration of commercial aqueous
reagents. For example, nitric acid is sold as a 70% (w/w) solution, meaning that the reagent contains 70 g of HNO3 per 100 g of solution.

Weight percent should more properly be called ______ and abbreviated m/m

_______ is commonly used to specify the concentration of a solution prepared by diluting a pure liquid compound with another liquid. For example, a 5% (v/v) aqueous solution of methanol usually describes a solution prepared by
diluting 5.0 mL of pure methanol with enough water to give 100 mL.

_______is often used to indicate the composition of dilute aqueous solutions of solid reagents. For example, 5% (w/v) aqueous silver nitrate often refers to a solution prepared by dissolving 5 g of silver nitrate in sufficient water
to give 100 mL of solution.

True or False: Do not always specify the type of percent when reporting
concentrations in this way

Answer 20

Weight percent

mass percent (weight percent is widely used in book)

Volume percent

Weight or volume percent

False

Question 21

For very dilute solutions, ________ is a convenient way to express concentration:

where cppm is the ______.

For even more dilute solutions,
_______ rather than 10^6 ppm is used in the previous equation to give the results in parts per billion (ppb).

The term ______ is also used, especially in oceanography

Answer 21

parts per million (ppm)

(formula)

concentration in parts per million

10^9 ppb

parts per thousand (ppt)

Question 22

The composition of a dilute solution is sometimes specified in terms of the volume
of a more concentrated solution and the volume of solvent used in diluting it

The volume of the former is separated from that of the latter by a _____.
Ex: 1:4 HCl
solution contains four volumes of water for each volume of concentrated hydrochloric acid.

dilution equation:

Answer 22

Solution-Diluent Volume Ratios

colon

Vconcd X cconcd + Vdil X cdil

Question 23

Scientists frequently express the concentration of a species in terms of its _____________.

The _____ is the negative logarithm (to the base 10) of the molar concentration of that species.

___ offer the advantage of allowing concentrations that vary over 10 or more orders of magnitude to be expressed in terms of
small positive numbers.

The best-known
p-function
is _____, which is the negative
logarithm of [H3O+]

Answer 23

p-function, or p-value

p-value

pX = -log [X]

p-values

pH

Question 24

The density of a substance is its mass per unit volume.

Expresses the mass of a
substance per unit volume. In SI units, density is expressed in units of ____________.

______Ratio of its mass to the mass of an equal volume of water at 4°C.

______Ratio of the
mass of a substance to the mass of an
equal volume of water.

Specific gravity is
_______ and so is not tied to any particular system of units. Widely used in describing items of commerce

Answer 24

Density

kg/L or g/mL

specific gravity

dimensionless

Question 25

_________ is the quantitative relationship among the amounts of reacting chemical species.

is the relationship among the number of moles of reactants and products as represented by a
balanced chemical equation.

Answer 25

Stoichiometry

Stoichiometry of a reaction

Question 26

An ______ gives the simplest whole number ratio of atoms in a chemical compound.

In contrast, a ________ specifies the number of atoms in a molecule.

State figure 2-2

A _______ provides additional information. Their structural formulas, C2H5OH and CH3OCH3, reveal structural differences between these compounds that are not shown in their common molecular formula.

Answer 26

empirical formula

molecular formula

structural formula

Question 27

A ______ is a statement of the combining ratios or stoichiometry (in units of moles) among the reacting substances and their products.

Often the physical state of
substances appearing in
equations is indicated by the letters:

(g), (l), (s), and (aq)

Answer 27

balanced chemical equation

Refer to gaseous, liquid, solid, and aqueous solution states

Question 28

______ is the most plentiful solvent on Earth, is easily purified, and is not toxic. It is, therefore, widely used as a medium for chemical analyses.

Answer 28

Water

Question 28

form ions when dissolved in water (or certain other solvents) and thus produce solutions that conduct electricity

_____ ionize essentially completely in a solvent.

Among the strong electrolytes listed are _____,______,______.

ionize only partially

Answer 28

electrolytes

Strong electrolytes

weak electrolytes

acids, bases, and salts

Question 29

An important feature of the Brønsted-Lowry concept is the idea that the product
formed when an acid gives up a proton is a potential proton acceptor and is called
the __________.

We refer to acid1 and base1 as a ______, or just a ________.

Similarly, every base accepts a proton to produce a ________.

When these two processes are combined, the result is an _____ or _____

Answer 29

conjugate base of the parent acid

conjugate acid-base pair

conjugate pair

conjugate acid

acid-base, or neutralization

Question 30

An acid ______.

A base _______.

Answer 30

donates protons

accepts protons

Question 31

An acid donates protons only in the presence of a
________.

Likewise, a base accepts
protons only in the presence of a
________.

A _______ is formed when
an acid loses a proton. For example,
acetate ion is the conjugate base of
acetic acid. Similarly, ammonium
ion is the conjugate acid of the base
ammonia.

A ______ is formed when a
base accepts a proton.

A _______ acts as an acid only in the presence of a base and vice versa.

Answer 31

proton acceptor
(a base)

proton donor (an acid)

conjugate base

conjugate acid

substance

Question 32

Species that have both acidic and basic properties

Answer 32

amphiprotic

Question 33

When dissolved in water,
an amino acid, such as glycine, undergoes a kind of internal acid-base reaction to
produce a ______

—a species or an ion that has both a positive and a negative charge.

Answer 33

zwitterion

Question 34

_____ is the classic example of an amphiprotic solvent

a solvent that can
act either as an acid or as a base, depending on the
solute.

Other common amphiprotic solvents are:

Answer 34

Water

methanol
ethanol
anhydrous acetic acid.

Question 35

behave as acids in the presence of basic solutes
and bases in the presence of acidic solutes.

Answer 35

Amphiprotic Solvents

Question 36

Amphiprotic solvents can undergo self-ionization, or ______, to form a pair of ionic species.

______ (also called
______) is the spontaneous
reaction of molecules of a substance to give a pair of ions.

Answer 36

Autoprotolysis or autoionization

Question 37

In figure 2-3. The first two are _____ because reaction with the solvent is sufficiently complete that no undissociated solute molecules are left in aqueous solution.

The rest are weak acids, which react incompletely with water to give solutions containing significant quantities of both the parent acid and its conjugate base.

Answer 37

strong acids

weak acids

Question 38

Swedish chemist, formulated many of the early ideas regarding the ionic dissociation in solution.

Suggest the relationship between the amount of carbon dioxide in atmosphere and global temperature, also called as greenhouse effect.

Answer 38

Svante Arrhenius

Question 39

In a ______, various
acids dissociate to different degrees and have different strengths.
Ex: _______

In a _______, several acids are completely dissociated and show the same strength. Ex: ______

Answer 39

differentiating solvent, Acetic Acid

leveling solvent, Water

Question 40

Many reactions used in analytical chemistry never result in complete conversion of reactants to products.

Instead, they proceed to a __________ in which the ratio of concentrations of reactants and products is constant.

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

True or False. The position of a chemical equilibrium is dependent of the route by which equilibrium is reached.

Answer 40

State of Chemical Equilibrium

Equilibrium Constant Expressions

False. Dependent - “independent”

Question 41

________states that the position of an equilibrium always shifts in such a direction as to relieve a stress that is applied to the system.

Answer 41

Le Châtelier’s principle

Question 42

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

Answer 42

mass-action effect

Question 42

Are the amount of reactants and products constant?

Why?

Answer 42

Equilibrium is a dynamic process.

Although chemical reactions appear to stop at equilibrium, in fact,

the amounts of reactants and products are constant because the “rates of the forward and reverse
processes are identical”.

Question 43

__________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 43

Thermodynamics

Question 44

The influence of concentration or pressure (if the participants are gases) on the
position of a chemical equilibrium is conveniently described in quantitative terms
by means of an_______.

Answer 44

equilibrium-constant expression

Question 45

In other words, the
number of moles of Ba(IO3)2 divided by the volume of the solid Ba(IO3)2 is constant
no matter how much excess solid is present. Therefore, the previous equation can be
rewritten;

where the new constant is called the….

Answer 45

Solubility-product constant or the solubility
product.

Question 45

Two chemist in field of thermodynamics. First to propose the law of mass action.

Answer 45

Cato Guldberg and Peter Waage

Question 46

The _______ is a mass-action effect predicted from Le Châtelier’s principle

Answer 46

common-ion effect