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SummerReviewPacket
The AP Chemistry course is designed to be the equivalent of the general chemistry course usually taken during the first college year. This course is taken with the idea in mind that students will take the AP Exam to receive college credit or placement at the student’s college of choice. For some students, this course enables them to undertake, in their first year, second-year work in the chemistry sequence at their institution or to register in courses in other fields where general chemistry is a prerequisite. For other students, the AP Chemistry course fulfills the laboratory science requirement and frees time for other courses. It is strongly recommended that students not only maintain a lab notebook throughout their AP Chemistry course but that students keep their notebook to show to the chemistry department head of the institution to which they wish to attend for review for credit or placement. Credit and placement tied to the AP Chemistry exam could lead to students' readiness for and engagement in the study of advanced topics in subsequent college courses and eventually the achievement of a STEM degree and successful career. The course centers around six big ideas and seven science practices:
Big Ideas
1. Structure of Matter
2. Bonding and Intermolecular Forces
3. Chemical Reactions
4. Kinetics
5. Thermodynamics
6. Chemical Equilibrium
(exert from CollegeBoard.org)
The following note pages, and readings, review the material you learned, or should have learned, in Honor Chemistry.
As stated above AP chemistry focuses on six (6) Big Ideas that define the practice of chemistry. Please look over the
following topics and concepts, read any material that is unclear. In the course we will expand on these ideas but you are
expected to have the foundations that follow.
The AP chemistry curriculum is VERY packed and I will be hard pressed to cover all the material before May 1st
, 2017 if I
have to go back over ALL the material from honors chemistry. I will do a brief over view of this material but I will not be
able to cover it in full. Please keep up at least this basic knowledge and you will be well prepared when we expand on it.
Additionally, you MUST know how to name compound before starting class. Please learn chemical nomenclature and
memorize the assigned polyatomic ions BEFORE the start of class. Notes on nomenclature can be found in this packet
and video tutorials can be found online. The lab at the end this packet is due by the second week of school (around
September 12th
) for your first lab grade.
Throughout the summer I will host two (2) 90 minute tutorials to go over the introductory material and nomenclature.
The dates for those tutorials are: Aug. 23rd
and Aug. 30th
at 1:00pm in the library.
Join the text remind system by texting the number 81010 the message “@villapchem”.
Go to LundquistLabs.com for more information.
SummerReviewBig Ideas from Honors Chemistry
AP Chemistry Big Idea 1: The chemical elements are fundamental building materials of matter,
and all matter can be understood in terms of arrangements of atoms. These atoms retain
their identity in chemical reactions.
Prior Knowledge – AP chemistry Big Idea 1 Further
Explanation
1A: All matter is made of atoms. There are a limited number of types of
atoms; these are the elements.
• Atomic theories have developed over time according to the available experimental evidence and
the interpretation of this evidence. Theories of atomic structure have evolved from ideas of
atoms as small, indestructible spheres to the current model, which indicates that an atom has a
very small nucleus composed of protons and neutrons. The nucleus is surrounded by electrons
that take up most of the space in an atom.
• Historical experiments are limited to models developed by Dalton, Thompson, Rutherford, Bohr,
and Schrödinger. Students should not be expected to memorize the names and the experiments.
Students should focus on how experimental evidence has led to changes in the atomic model.
• Because the mass of an atom is very small, the mole is used to translate the mass of an atom to
the macroscopic level. The mass of a mole of any substance is equal to its formula mass in grams.
• A mole is used as a counting unit, like a dozen.
You’re not expected to memorize Avogadro’s number or use it explicitly in calculations (e.g.,
calculate the number of oxygen atoms in 10 grams of carbon dioxide).
• The reference for atomic masses is carbon‐12. One atomic mass unit (amu) equals 1/12 of the
mass of a carbon‐12 atom.
• The standard unit of concentration is molarity (mol/L), which is a measure of the amount of a
substance in solution.
2.4 to 2.5
p. 47 to 51
3.3
p. 81 to 8.7
8.4
p. 136 to 141
1B: The atoms of each element have unique structures arising from
interactions between electrons and nuclei.
• Protons are positively charged particles that define the chemical identity of an element.
Neutrons have no charge and have approximately the same mass as a proton.
• The nucleus is surrounded by negatively charged electrons that have a relatively small mass
compared to that of protons and neutrons. Electrons occupy most of the volume of an atom.
• The protons and electrons in an atom are equal in number.
• An ion is a species in which the number of electrons is not equal to the number of protons.
• It is difficult to predict exactly where electrons are located. Nevertheless, the exact energies of
electrons can be measured, and regions where electrons are most likely located can be defined.
2.5
p. 50 to 54
Prior Knowledge – AP chemistry Big Idea 1 Further
Explanation
1.C: Elements display periodicity in their properties when the elements are
organized according to increasing atomic number. This periodicity can be
explained by the regular variations that occur in the electronic structures of
atoms. Periodicity is a useful principle for understanding and predicting
trends in atomic properties, in the composition of materials, and generating
ideas for designing new materials.
• The modern version of the periodic table is organized in order of increasing atomic number
(number of protons).
• Elements were originally placed in the periodic table based on their repeating properties, which
are a result of the number and type of valence electrons.
• Properties of an element can be predicted based on its placement in the periodic table. Groups
of elements exhibit similar properties with predictable variations; rows of elements have
predictable trends.
• Elements are often classified as metals, nonmetals or metalloids.
• There are a number of elements— such as nitrogen, oxygen, phosphorus, sulfur, hydrogen and
carbon— that are important for living systems. Carbon, the most important of these elements, is
central to the chemistry of biological systems because of its unique bonding characteristics.
Carbon compounds are usually classified as organic compounds.
NO Organic nomenclature for now.
• Another way to use the periodic table is to consider the elements as arranged in “blocks” based
on the elements’ outermost electrons. The elements in these blocks (s‐block, transition metals,
p‐block, lanthanides and actinides) in the modern periodic table also have similar properties of
predictable variability.
You only need to remember the s‐block and the p‐block in detail for now.
• Based on the current atomic model, electrons can be considered as clouds of electron density,
rather than as particles orbiting the nucleus.
• The position of electrons is best described as orbitals that represent the probability of finding an
electron in a region of space.
Electrons exhibit characteristics of both particles and waves. This is a property of particles at the
atomic‐molecular level. While this is beyond the scope of the class it is useful to know
• Electrons usually occupy the lowest available energy orbitals (ground state).
• Each orbital can describe the probability for a maximum of two electrons. Different types of
orbitals are represented by lowercase letters (e.g., s, p, d, and f). Each type of orbital has a
different shape(e.g., s has a spherical shape and p has a dumbbell shape).
2.7
p. 54 to 57
7.11
p. 312 to 318
Prior Knowledge – AP chemistry Big Idea 1 Further
Explanation
1.D. Atoms are so small that they are difficult to study directly; atomic
models are constructed to explain experimental data on collections of atoms.
• Symbolic representations allow for the visualization of atoms and molecules that are too small to
see with conventional microscopes and for the prediction of the properties of these atoms and
molecules.
• Electrons have been observed to have definite energy levels, with no values in between. When
an electron moves from one energy level to another, it emits or absorbs a photon that has
energy equal to the energy difference between the levels. Consequently, each element has a
unique emission or absorption spectrum.
• Both the emission and absorption spectra can be used to identify elements wherever they are
located.
FIREWORKS
p. 298 to 299
1.E. Atoms are conserved in physical and chemical processes, but not in
nuclear processes.
• Atoms are central to the principle of the conservation of matter.
• When a change occurs, the total number of atoms within a closed system remains the same;
therefore, the total mass of the system remains the same.
• Different kinds of models or representations give different information about materials. For
example, ball‐and‐stick models provide information about shape and bond angles; space‐filling
models give information about surface features.
• All of the elements, except hydrogen and helium, originated from the nuclear fusion reactions of
stars. This production of heavier elements from lighter elements by stellar fusion has never
ceased and continues today.
• Chemical reactions involve electrons; nuclear reactions involve only changes in the nucleus.
Neutrons have little effect on how an atom interacts with other atoms, yet the number of
neutrons does affect the mass and stability of the nucleus. Atoms with the same number of
protons and a different number of neutrons are called isotopes.
• When an atom has an unstable nucleus, the unstable nucleus emits radiation (e.g. alpha, beta,
gamma and positron). This process, called radioactive decay, increases the stability of the
nucleus. Atoms with an unstable nucleus are often called radioisotopes.
• Half‐life is a measure of the rate of radioactive decay, or the amount of time it takes for half of a
radioactive sample to decay to its products. For any radioisotope, the half‐life is constant and
unique and can be used to determine the age of the material.
• Radioisotopes have several medical applications. The radiation emitted as a result of the
unstable nucleus has high energy and can be detected. These characteristics allow radioisotopes
to be used as tracers of biological processes and to kill biological materials (e.g., cancer cells).
3.8 & 3.9
p. 97 to 102
19.1 to 19.3
873 to 883
Prior Knowledge – AP chemistry Big Idea 1 Further
Explanation
1.E. Atoms are conserved in physical and chemical processes, but not in
nuclear processes. (continued)
• Fission, the splitting of a nucleus into small fragments, and fusion, the combining of two nuclei,
are types of nuclear reactions.
• When a nuclear reaction occurs, the mass–energy interconversion is significant. Nuclear
reactions, such as fission and fusion, are accompanied by large energy changes that are much
greater than those that accompany chemical reactions.
• Nuclear reactions can be used as a controlled source of energy (e.g., a nuclear power plant).
AP Chemistry Big Idea 2: Chemical and physical properties of materials can be explained by
the structure and arrangement of atoms, ions, or molecules and the forces between them.
Prior Knowledge – AP chemistry Big Idea 2 Further
Explanation
2.A. Matter can be described by its physical properties. The physical
properties of a substance generally depend on the spacing between the
particles (atoms, molecules, ions) that make up the substance and the forces
of attraction among them. • The physical properties of materials are determined by the strength of the attractions (bonds or
intermolecular forces) between particles.
• Matter can be represented at three different levels: macroscopic, atomic–molecular and
symbolic. The macroscopic level is observable in the real‐world setting. The atomic‐molecular
level is often represented by visual representations, including animations. The symbolic level
includes elemental symbols, chemical formulas and equations, and Lewis diagrams.
• The atomic–molecular level structure of matter determines both the macroscopic structure and
the properties of the material.
• There are four states of matter: solid, liquid, gas and plasma.
• The existence and behavior of matter in the solid, liquid, gas or plasma state can be explained by
the atomic–molecular theory (the idea that matter is composed of small particles).
• In a gas, the particles have enough kinetic energy to overcome any attractions. Generally, the
separation between gas particles is such that their interactions are minimal.
• For a given substance, the temperature (and, therefore, the average kinetic energy) needed for a
change of state to take place depends on the attractions between the particles in that substance.
In other words, the temperature at which a change of state takes place depends on the amount
of energy that is required to overcome the attractions between the particles.
• Vapor pressure occurs when the particles of solids and liquids have enough kinetic energy to
enter the vapor (gas) state. Vapor pressure increases with temperature. Liquids boil when their
vapor pressure reaches atmospheric pressure.
• The behavior of a given quantity of gas can be described in terms of its pressure, volume and
temperature.
• Each state of matter has a predictable behavior that depends on the chemical composition of the
substance and the attractions between particles of that substance.
• When a substance changes state, the relative arrangement of the particles changes, as well as
the distance between these particles. The atoms that make up the particles of the substance are
not rearranged to form a new substance.
• When thermal energy is added to a solid, liquid or gas, most substances increase in volume
because the particles have increased kinetic energy, causing a greater distance between the
particles.
• For most substances, the distance between particles increases as they change from solid to liquid
togas, meaning that the density of a solid is usually greater than the density of a liquid. The
density of a liquid is always greater than the density of a gas.
10.1 to 10.2
p. 440 to 445
Prior Knowledge – AP chemistry Big Idea 2 Further
Explanation
2.A. Matter can be described by its physical properties. The physical
properties of a substance generally depend on the spacing between the
particles (atoms, molecules, ions) that make up the substance and the forces
of attraction among them. (continued)
• Because solid water has an extensive network of hydrogen bonds that gives it an open structure,
the density of solid water is less than that of liquid water. When water freezes, its volume
expands.
• The kinetic–molecular theory (KMT) is an explanation of the macroscopic properties (e.g.,
pressure, temperature, and volume) of gases, using the idea of particle interactions and motions.
• In a solid, the kinetic energy of the particles making up the substance is not great enough to
overcome the attractions holding them together. Although the particles vibrate in place, the
distance between them does not increase.
• In a liquid, the kinetic energy of the particles making up the substance is sufficient to overcome
the attractions, thereby allowing the particles to move relative to each other. Most of the
particles, however, do not have enough kinetic energy to completely overcome the attractions
and enter the gas state.
2.B. Forces of attraction between particles (including the noble gases and also
different parts of some large molecules) are important in determining many
macroscopic properties of a substance, including how the observable physical
state changes with temperature.
• Intermolecular forces (IMFs) can be predicted based on the shape of the molecule and the
polarities of the bonds.
• The shape and polarity of the molecules of a substance determine the relative strength of its
intermolecular forces (IMFs).
• There are several types of IMFs, including the following: London dispersion forces (present in all
molecules), dipole–dipole (present in polar molecules) and hydrogen bonding (a special case of
dipole–dipole).
• Molecular compounds generally have melting and boiling points that are dependent on their
molar mass and IMFs.
• A solute will usually be most soluble in a solvent that has similar IMFs.
• Many substances dissolve in water (a polar solvent). Consequently, water is a very useful and
familiar solvent.
• Many ionic compounds dissolve in water. In order for this to occur, the forces of attraction
between the ions in the solid must be overcome by the ion–dipole interactions with the water.
8.2 to 8.3
p. 344 to 349
10.1
p. 440 to 443
11.3
p. 504 to 509
Prior Knowledge – AP chemistry Big Idea 2 Further
Explanation
2.C. The strong electrostatic forces of attraction holding atoms together in a
unit are called chemical bonds. • The forces of attraction between the particles in molecules, ionic lattices, network covalent
structures or materials with metallic properties are called chemical bonds.
• Atoms can bond to form molecules, ionic lattices, network covalent structures or materials with
metallic properties. Each of these types of structures has different, yet predictable, properties
that depend on the identity of the elements and the types of bonds formed.
• When elements bond they form compounds that are named in systematic ways.
• The bonds in most compounds fall on a continuum between the two extreme models of bonding:
ionic and covalent.
• An ionic bond involves the attraction between two oppositely charged ions, typically a positively
charged metal ion and a negatively charged nonmetal ion. An ion attracts oppositely charged
ions from every direction, resulting in the formation of three‐dimensional lattices.
• Covalent bonds typically involve at least two electrons shared between the bonding atoms.
Nonmetal atoms usually combine by forming one or more covalent bonds between atoms.
Covalent bonding can result in the formation of structures ranging from small molecules to large
molar mass biopolymers and three‐dimensional lattices (e.g., a diamond).
• Only electrons in the highest energy state (valence electrons) are involved in bonding.
• A polar covalent bond forms between two atoms with different electronegativities; the
magnitude of the polarity of the bond depends on the electronegativity difference and the
distance between the atoms (bond length).
• The atomic–molecular level structure of simple molecules can be represented symbolically in two
or three dimensions as molecular formulas, structural formulas (Lewis diagrams), ball‐and‐stick
models or space‐filling models. Each of these symbolic representations can provide some unique
information about the structure of the substance, as well as some information that is common to
all the models.
• Two‐dimensional representations (Lewis diagrams) can be drawn by using a set of simple rules.
• Lewis diagrams provide a foundation for predicting three‐dimensional electron pair geometries
and three‐dimensional shapes of simple molecules.
• The atoms of many elements are more stable when they are bonded with other atoms.
• When two isolated atoms bond in the gas phase, energy is released to the surroundings,
resulting in a lower energy system.
• Different kinds of models are more appropriate for representing different chemical substances
(e.g., ionic and covalent network species are best represented by models that incorporate
elements of the lattice structure).
• Compounds that have three‐dimensional lattice networks of bonds, either ionic or covalent, have
very high melting and boiling points because bonds must be broken in order to change state from
solid to liquid to gas.
2.6 to 2.7
p. 52 to 54
8.1
p. 340 to 344
8.4 to 8.6
350 to 357
8.2 to 8.3
p. 342 to 344
8.10 tp 8.11
p. 365 to 371
p.414
AP Chemistry Big Idea 3: Changes in matter involve the rearrangement and/or reorganization
of atoms and/or transfer of electrons.
Prior Knowledge – AP chemistry Big Idea3 Further
Explanation
3.A. Chemical changes are represented by a balanced chemical equation that
identifies the ratios with which reactants react and products form.
• When a chemical change occurs, the numeric relationship between the reactants and products is
determined at the atomic–molecular level. In order to translate this relationship from the
atomic–molecular level to the macroscopic level, the mole and the formula mass in grams are
used as a measure of the amount of substance.
• A balanced chemical reaction represents the conservation of matter at both the atomic–
molecular level and the macroscopic level by showing the relationship between the reactants
and products.
• A stoichiometric calculation is a conversion from one amount (mass, mole, volume of gases,
volume of solutions) of substance in any chemical change to another amount and can be made as
long as the relationships among all of the reactants and all of the products at the molecular level
are known.
• In very large molecules, a specific region may have predictable polarities and reactivities based
on the structural features of that region.
3.10
p. 102 to 107
3.B. Chemical reactions can be classified by considering what the reactants
are, what the products are, or how they change from one into the other.
Classes of chemical reactions include synthesis, decomposition, acid‐base and
oxidation‐reduction reactions.
• Many acids and bases contain covalent bonds but may undergo reactions (e.g., reactions with
water) that result in the production of an ionic species.
• The formation of a precipitate or a molecular compound, in a chemical reaction between ionic
compounds in aqueous solution, often occurs because the new ionic or covalent bonds are
stronger than the original ion–dipole interactions of the ions in solution.
• There are structural features of molecules that can give rise to specific kinds of reactivity (e.g.,
acidity often results when hydrogen is covalently bonded to an electronegative element).
• The acidity of an aqueous solution is often expressed as pH, where pH is related to the
concentration of the hydronium ion.
• A common class of reactions (oxidation reactions) often involves the reaction of oxygen with
carbon compounds.
The common reaction classifications of single/double replacement, synthesis/decomposition, and
combustions, often lead to misconceptions because they are not based on the actual chemistry, but
on surface features that may be similar from one system to another , even though the underlying
chemistry is not the same. Therefore, these types of reaction classifications will be ignored and we
will learn new ones.
4.4
p. 144
4.5
p. 145
14.3
p. 647 to 650
Prior Knowledge – AP chemistry Big Idea3 Further
Explanation
3.C Chemical and physical transformations may be observed in several ways
and typically involve a change in energy
• When a substance dissolves in water, it is sometimes difficult to determine whether the process
is a physical or chemical change.
• Students are not required to determine whether dissolution is a physical or chemical process.
They can participate in an investigation of a solution of a salt in order to understand that a clear
distinction may not always be determined for certain processes.
• The process of dissolving a solute in a solvent may be considered a reaction, and the process is
affected by many of the same factors (temperature, intermolecular forces and surface area) that
affect reaction rates.
• A chemical reaction can be considered a system. The reaction is a result of breaking bonds
and/or overcoming IMFs in reactants, and of forming new bonds and/or IMFs in products.
• In general, energy is transferred out of a system (exothermic) when the products have stronger
bonds than those in the reactants. Energy is transferred into the system (endothermic) when the
products have weaker bonds than those in the reactants.
4.2
p. 132 to 136
6.1
p. 238 to 242
AP Chemistry Big Idea 4: Rates of chemical reactions are determined by details of the
molecular collisions
Prior Knowledge – AP chemistry Big Idea 4 Further
Explanation
4.A. Reaction rates which depend on temperature and other environmental
factors, are determined by measuring changes in concentrations of reactants
or products over time.
• The rate of reaction can be defined as the change in the amount of products or reactants per unit
of time.
• The rates at which reactions occur are affected by factors such as concentration, pressure,
temperature and the addition of a catalyst.
4.B. Elementary reactions are mediated by collisions between molecules. Only collisions having
sufficient energy and proper relative orientation of reactants lead to products.
• All stable species require the input of energy to initiate a reaction. The amount of energy
required is called the activation energy barrier.
• When the concentrations/pressures of the reactants are increased, the probability of a molecular
collision increases. Because a molecular collision may lead to a reaction, the rate of reaction
increases as the probability of a molecular collision increases.
• When the kinetic energy of the reactants increases, indicated by a rise in temperature, the
probability of a molecular collision increases. When molecules/atoms collide with increased
energy, they are more likely to react.
• In order for reactions to occur, the reacting particles must collide in the appropriate orientation
and with enough energy. Not all collisions are effective.
• Most reactions occur in solution or in the gas state because the reacting particles are free to
move and can collide and interact with each other. Reactions among solids are not as prevalent
because a reaction can only occur at the surface of a solid.
12.6
p 565 to 567
4.D. Reaction rates may be increased by the presence of a catalyst. Catalysts, such as enzymes in biological systems and the surfaces in an automobile's catalytic
converter, increase the rate of a chemical reaction. Catalysts may function by lowering the activation
energy of an elementary step in a reaction, thereby increasing the rate of that elementary step but
leaving the mechanism of the reaction otherwise unchanged. Other catalysts participate in the
formation of a new reaction intermediate, thereby providing a new reaction mechanism that provides
a faster pathway between reactants and products.
• The addition of a catalyst provides an alternate pathway for reactions to occur, usually with a
lower activation energy barrier. More molecules therefore have enough energy to overcome the
activation energy barrier, leading to an increased rate of reaction.
• One of the functions of an enzyme is to hold molecules in an orientation that can lead to a
reaction.
12.7
p. 570 to 577
AP Chemistry Big Idea 5: The Laws of thermodynamics describe the essential role of energy
and explain, and predict, the direction of changes in matter.
Prior Knowledge – AP chemistry Big Idea 5 Further
Explanation
5.A. Two systems with different temperatures that are in thermal contact will
exchange energy. The quantity of thermal energy transferred from one
system to another is called heat.
• Temperature is a measure of the average kinetic energy of all particles in a substance.
Temperature is independent of the amount of matter present, while thermal energy is
dependent on the amount of matter present.
• Thermal energy transfer (heat) occurs from a warm object to a cooler object.
• The part of the universe that is being studied is called a system. A real or imaginary boundary
separates the system from the rest of the universe, or the surroundings. By defining a system,
any change the system undergoes can be tracked.
• A closed system does not interact with its surroundings — matter and energy cannot get into or
out of the system. Most systems of interest in our everyday lives are open systems — matter and
energy can be transferred into or out of the system.
• If energy moves from a system to its surroundings, the temperature of the surroundings will
increase. This is often described as an exothermic process. If energy moves from the
surroundings to a system, then the temperature of the surroundings will decrease. This is often
described as an endothermic reaction. Temperature changes in large surroundings may not be
detectable.
• Thermal energy is the energy associated with the movement (translational, rotational and
vibrational)of all particles in a system. Although thermal energy cannot be directly measured, the
effects of changes in the thermal energy of the system can be observed and calculated.
• In the “real world,” thermal energy and heat are often used synonymously; however, in the
physical sciences the term “heat” is reserved for the transfer of thermal energy (e.g., from a hot
object to a cold object). For the purposes of this standards document, and in order to avoid
misunderstandings, the terms “thermal energy” and “thermal energy transfer” are used.
• At the atomic–molecular scale, thermal energy is associated with the kinetic energy of molecules.
As the thermal energy increases, the molecules move (translate, rotate and vibrate) faster.
• The thermal energy of an object depends on its mass, temperature and chemical composition.
• When energy is transferred (e.g., from the exothermic reaction system to the surroundings),
some of the energy (in the form of thermal energy) always becomes less available to bring about
change. Consequently, the amount of useful energy decreases over time, even though the total
energy is constant.
6.1
p. 238 to 241
Prior Knowledge – AP chemistry Big Idea 5 Further
Explanation
5.B. Energy is neither created nor destroyed but only transformed from one
form to another.
• Mass–energy is always conserved for all defined systems, for all types of interactions, and at all
scales.
• In chemical systems, the interconversion of mass and energy is negligible. Therefore, in chemical
systems only energy changes need to be considered; mass–energy conversions need not be
considered.
• The total energy of a chemical system is impossible to measure. When a chemical system reacts,
its energy change can be measured by observing the effect of that change on a property of a
substance within the system (e.g., the temperature of water is easily measured and can be related
to changes in energy).
• At the atomic–molecular scale, electromagnetic radiation (photons) is absorbed by molecules.
Some of this radiation can be transformed into kinetic energy (molecules vibrate and move faster)
that appears as thermal energy and causes a rise in temperature.
5.E. Chemical or physical processes are driven by a decrease in enthalpy or an increase in entropy,
or both.
• Entropy is a measure of the number of possible arrangements of atoms, molecules or energy in a
system — the more possible arrangements, the more entropy the system has. Any
thermodynamically favored process is accompanied by an increase in the total entropy (i.e., the
entropy of the universe)and in the dispersion of energy.
While entropy is commonly discussed in terms of randomness or disorder, this can lead to significant
misconceptions — including the idea that systems cannot spontaneously become more organized. On
the contrary, increases in entropy often drive the organization of systems (e.g., protein folding and
micelle formation).
17.1
p. 773 to 778
AP Chemistry Big Idea 6: Any bond or intermolecular attraction that can be formed can be
broken. These two processes are in a dynamic competition, sensitive to initial conditions and
external perturbations.
Prior Knowledge – AP chemistry Big Idea 6 Further
Explanation
6.A. Chemical equilibrium is a dynamic, reversible state in which rates of
opposing processes are equal.
• All reactions are reversible, and many reactions do not proceed completely toward products. This
does not mean that the reaction has stopped, but rather that the rate of the reverse reaction is
equal to the rate of the forward reaction.
• •Although some reactions appear to proceed only in one direction, the reverse reaction can
occur; however, the occurrence of the reverse reaction is highly unlikely (e.g., combustion
reactions).
13.1
p. 594 to 597
6.B. Systems at equilibrium are responsive to external perturbations, with the
response leading to a change in the composition of the system.
• According to Le Chatelier’s principle, if a chemical system at equilibrium is disturbed by a change
in the conditions (e.g., temperature, pressure on gaseous equilibrium systems, concentration) of
the system, then the equilibrium system will respond by moving to a new equilibrium state,
reducing the effect of the change.
13.7
p. 620 to 626
6.D. The equilibrium constant is related to temperature and the difference in
Gibbs free energy between reactants and products.
• Reactions that appear to proceed only in one direction usually release a large amount of energy.
An input of energy is required to make such a reaction go backwards.
• An unfavorable reaction can be made to occur by removing products as they are formed. The
removal of products forces the system to shift its equilibrium position.
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try
–is
def
ined
as
the
stu
dy
of
mat
ter
and
en
erg
y a
nd
mo
re i
mp
ort
antl
y,
the
chan
ges
bet
wee
n t
hem
Wh
y s
tud
y c
hem
istr
y?
-b
eco
me
a b
ette
r p
roble
m s
olv
er i
n a
llar
eas
of
yo
ur
life
-sa
fety
–h
ad t
he
Ro
man
’s u
nd
erst
oo
d l
ead
po
iso
nin
g,
thei
r ci
vil
izat
ion
wo
uld
no
t h
ave
fall
en
-to
bet
ter
un
der
stan
d a
ll a
reas
of
scie
nce
Th
e S
cien
tifi
c M
eth
od
A p
lan
of
atta
ck!
Th
e fu
nd
amen
tal
step
s o
f th
e
scie
nti
fic
met
ho
d
*A
P i
s a
regis
tere
d t
radem
ark o
f th
e C
oll
ege
Boar
d,
whic
h w
as n
ot
involv
ed i
n t
he
pro
duct
ion o
f th
is p
roduct
.©
20
13
by
Ren
é M
cCorm
ick.
All
rig
hts
rese
rved
.
Go
od
exp
erim
enta
l d
esig
n c
oup
led
wit
h r
epet
itio
nis
key
!
Th
eory
–h
yp
oth
eses
are
ass
emb
led i
n a
n a
ttem
pt
at e
xpla
inin
g“w
hy
” th
e “w
hat
” h
appen
ed.
Mo
del
–w
e u
se m
any
mo
del
s to
exp
lain
nat
ura
l ph
eno
men
on
–w
hen
new
ev
iden
ce i
s fo
un
d,
the
mo
del
ch
ang
es!
Ro
ber
t B
oy
le
olo
ved
to e
xper
imen
t w
ith a
ir
ocr
eate
d t
he
firs
t vac
uu
m p
um
p
oco
in a
nd
fea
ther
fel
lat
th
e sa
me
rate
du
e to
gra
vit
y
oin
a v
acu
um
th
ere
is n
oai
rre
sist
ance
to
im
ped
e th
e fa
ll o
f ei
ther
ob
ject
!
oB
oy
le d
efin
ed e
lem
ents
as
any
thin
g t
hat
can
not
be
bro
ken
into
sim
ple
r su
bst
ance
s.
Bo
yle
’s G
as L
aw:
P1V
1=
P2V
2
Sci
enti
fic
La
ws
–a
sum
mar
y o
f ob
serv
ed (
mea
sura
ble
) b
ehav
ior
[a t
heo
ry i
s an
expla
nat
ion
of
beh
avio
r]
A l
aw
su
mm
ari
zes
wh
at
hap
pen
s; a
th
eory
(m
od
el)
is a
n a
ttem
pt
to e
xpla
in W
HY
it
hap
pen
s.
-L
aw
of
Co
nse
rva
tio
n o
f M
ass
–m
ass
reac
tants
=
mas
s p
rod
uct
s
-L
aw
of
Co
nse
rva
tio
n o
f E
ner
gy
–(a
.k.a
. fi
rst
law
of
ther
mo
dy
nam
ics)
En
erg
y C
AN
NO
T b
e cr
eate
d N
OR
des
troye
d;
can
on
ly c
ha
ng
e fo
rms.
-S
cien
tist
sar
e h
um
an a
nd
sub
ject
ed t
o
Dat
a m
isin
terp
reta
tio
ns
Em
oti
on
al a
ttac
hm
ents
to
th
eori
es
Lo
ss o
f ob
ject
ivit
y
Po
liti
cs
Eg
o
Pro
fit
mo
tiv
es
Fad
s
War
s
Rel
igio
us
bel
iefs
Ga
lile
o–
forc
ed t
o r
ecan
t h
is a
stro
no
mic
al o
bse
rvat
ion
s in
the
face
of
stro
ng
rel
igio
us
resi
stan
ce
La
vo
isie
r–
“fat
her
of
mo
der
n c
hem
istr
y”;
beh
ead
ed d
ue
to p
oli
tica
l af
fili
atio
ns.
Th
e n
eed
fo
r b
ette
r ex
plo
siv
es;
(ra
pid
ch
ang
e o
f so
lid
dia
met
ers
fart
her
ap
art
and
ex
ert
mas
sive
forc
es a
s a
resu
lt)
for
war
s h
ave
led t
o
-fer
tili
zers
th
at u
tili
zes
nit
rogen
-N
ucl
ear
dev
ices
Ch
emic
al F
ou
nd
atio
ns
2
Un
its
of
Mea
sure
A q
uan
tita
tiv
e ob
serv
atio
n,
or
mea
sure
men
t, A
LW
AY
S c
on
sist
s o
f tw
o p
arts
: a
nu
mb
eran
d a
un
it.
Tw
o m
ajor
mea
sure
men
ts s
yst
ems
exis
t: E
ngli
sh (
US
an
d s
om
e o
f A
fric
a) a
nd
Met
ric
(th
e re
st o
f th
e g
lob
e!)
SI
syst
em–
19
60
an
in
tern
atio
nal
agre
emen
t w
as r
each
ed t
o s
et u
p a
sy
stem
of
un
its
so s
cien
tist
s ev
ery
wh
ere
cou
ld b
ette
r co
mm
un
icat
e m
easu
rem
ents
. L
e S
yst
ème
Inte
rnat
ion
al i
n F
ren
ch;
all
bas
ed u
po
n o
r d
eriv
ed f
rom
the
met
ric
syst
em
KN
OW
TH
E U
NIT
S A
ND
PR
EF
IXE
Ssh
ow
n i
n B
LU
E!!
!
Vo
lum
e–
der
ived
fro
m l
eng
th;
con
sid
er a
cub
e 1
m o
n e
ach
ed
ge
1.0
m3
-A
dec
imet
er i
s 1
/10
of
a m
eter
so
(1m
)3=
(1
0d
m)3
=1
03
dm
3=
1,0
00
dm
3
1d
m3
= 1
lit
er (
L)
and
is
slig
htl
y l
arger
th
an a
quar
tal
so
1d
m3
= 1
L =
(1
0cm
)3=
10
3cm
3=
1,0
00
cm
3=
1,0
00
mL
AN
D1
cm3
= 1
mL
= 1
gra
m o
f H
2O
(at
4ºC
if
you w
ant
to b
e pic
ky
)
Mas
s v
s. W
eig
ht
–ch
emis
ts a
re q
uit
e g
uil
ty o
f u
sin
g t
hes
e te
rms
inte
rchan
gea
bly
.
om
ass
(g o
r k
g)
–a
mea
sure
of
the
resi
stan
ce o
f an
ob
ject
to a
ch
ang
e in
its
sta
te o
f m
oti
on
(i.
e.ex
hib
its
iner
tia)
; th
e q
uan
tity
of
mat
ter
pre
sen
t
ow
eig
ht
(a f
orc
ehas
unit
s o
f N
ewto
ns)
–th
e re
spo
nse
of
mas
s to
gra
vit
y;
sin
ce a
ll o
f ou
r m
easu
rem
ents
wil
l b
e m
ade
her
e o
n E
arth
, w
e co
nsi
der
th
e ac
cele
rati
on
du
e to
gra
vit
y a
co
nst
ant
so w
e’ll
use
th
e te
rms
inte
rch
ang
eab
ly a
s w
ell
alt
ho
ug
hit
is
tech
nic
ally
in
corr
ect!
We
“wei
gh
” ch
emic
al q
uan
titi
es o
n a
ba
lan
ceN
OT
a s
cale
!!
Ch
emic
al F
ou
nd
atio
ns
3
Ph
ysi
cs c
on
nec
tio
n:
Fw
=m
a
Fw
=m
g
2
9.8
m
sw
mF
its
un
its
are
2
mk
g
sN
Ex
erci
se
1P
reci
sion
an
d A
ccu
racy
To
ch
eck
the
accu
racy
of
a g
rad
uat
ed c
yli
nd
er,
a st
ud
ent
fill
ed t
he
cyli
nder
to
th
e
25-m
L m
ark
usi
ng
wat
er d
eliv
ered
fro
m a
bu
ret
and
th
en r
ead t
he
vo
lum
e d
eliv
ered
.
Fo
llo
win
g a
re t
he
resu
lts
of
fiv
e tr
ials
:
Tri
al
V
olu
me
Sh
ow
n b
y
Vo
lum
e S
ho
wn
Gra
du
ate
d C
ylin
der
by
the
Bu
ret
12
5 m
L2
6.5
4 m
L
22
5 m
L2
6.5
1 m
L
32
5 m
L2
6.6
0 m
L
42
5 m
L2
6.4
9 m
L
52
5 m
L2
6.5
7 m
L
Ave
rag
e2
5m
L2
6.5
4m
L
Is t
he
gra
duat
ed c
yli
nd
er a
ccura
te?
Note
th
at
the
av
erag
e v
alu
e m
easu
red
usi
ng
th
e b
ure
t is
sig
nif
ica
ntl
y d
iffe
ren
t fr
om
25 m
L. T
hu
s, t
his
gra
du
ate
d c
yli
nd
er i
s n
ot
ver
y a
ccu
rate
. I
t p
rod
uce
s a
sy
stem
ati
c er
ror
(in
th
is
case
, th
e in
dic
ate
d r
esu
lt i
s lo
w f
or
each
mea
sure
men
t).
Gra
vit
y–
var
ies
wit
h a
ltit
ude
her
e on
pla
net
Ear
th
Th
ecl
ose
r y
ou
are
to
the
cen
ter
of
the
Ear
th, th
e st
ron
ger
th
e g
rav
itat
ion
al f
ield
SIN
CE
it
ori
gin
ates
fro
m t
he
cente
r of
the
Ear
th.
Ev
ery
ob
ject
has
a g
ravit
atio
nal
fie
ld –
as l
on
g a
s y
ou
’re
on
Ear
th, th
ey a
re m
ask
ed
sin
ce t
he
Ear
th’s
fie
ld i
s so
HU
GE
co
mp
ared
to
the
ob
ject
’s.
Th
e st
ren
gth
of
the
gra
vit
atio
nal
fie
ld
mas
s
Ev
er s
een a
stro
nau
ts i
n s
pac
e th
at a
re “
wei
gh
tles
s” s
ince
th
ey a
re v
ery
far
rem
ov
ed
fro
m t
he
cen
ter
of
Ear
th?
No
tice
ho
w t
hey
are
con
stan
tly
“d
raw
n”
to t
he
sid
es o
f th
e
ship
an
d m
ust
pu
sh a
way
?
Th
e sh
ips’
mas
s is
gre
ater
th
an t
he
astr
on
aut’
s m
ass
“g”
is g
reat
er f
or
the
ship
an
d
the
astr
on
aut
is a
ttra
cted
to
th
e sh
ip j
ust
as
yo
u a
re a
ttra
cted
to
Ear
th!
The
mo
on
has
61
the
mas
s of
the
Ear
th
yo
u w
ou
ld e
xp
erie
nce
61
the
gra
vit
atio
nal
fie
ld y
ou
exp
erie
nce
on
Ear
th a
nd
y
ou
’d W
EIG
H
61
of
w
hat
yo
u w
eig
h o
n E
arth
.
Pre
cisi
on
an
d A
ccu
racy
-A
ccu
racy
–co
rrec
tnes
s; a
gre
emen
t o
f a
mea
sure
men
t w
ith
th
e tr
ue
val
ue
-P
reci
sion
–re
pro
du
cibil
ity
; d
egre
e o
f ag
reem
ent
amo
ng
sev
eral
mea
sure
men
ts.
-R
an
do
mo
r in
det
erm
ina
te e
rro
r–
equ
al p
robab
ilit
y o
f a
mea
sure
men
t b
ein
g
hig
h o
r lo
w
-S
yst
emati
co
r d
eter
min
ate
err
or
–o
ccu
rs i
n t
he
sam
e d
irec
tio
n e
ach
tim
e
The
resu
lts
of
sever
al
dar
t th
row
s sh
ow
the
dif
fere
nce
bet
wee
n
pre
cise
and a
ccura
te.
(a)
Nei
ther
nor
pre
cise
(la
rge
random
erro
rs).
(b)
Pre
cise
but
not
accu
rate
(sm
all
random
err
ors
, la
rge
syst
emat
ic e
rror)
.
(c)
Bull
’s-e
ye!
Both
pre
cise
and a
ccura
te
(sm
all
random
err
ors
,
no s
yst
emat
ic e
rror)
.
Ch
emic
al F
ou
nd
atio
ns
4
Sig
nif
ica
nt
Fig
ure
s a
nd
Ca
lcu
lati
on
s
Det
erm
inin
g t
he
Nu
mb
er o
f S
ign
ific
an
t F
igu
res
(or
Dig
its)
in
a M
easu
rem
ent
No
nze
ro d
igit
s ar
e si
gn
ific
ant.
(E
asy
en
ou
gh
to
iden
tify
!)
A z
ero
is
sign
ific
ant
IF a
nd
ON
LY
IF
it
mee
ts o
ne
of
the
con
dit
ion
s bel
ow
:
-T
he
zero
in
qu
esti
on
is
“ter
min
atin
g A
ND
rig
ht”
of
the
dec
imal
[m
ust
be
bo
th]
-T
he
zero
in
qu
esti
on
is
“san
dw
ich
ed”
bet
wee
n t
wo
sig
nif
ican
t fi
gu
res
Ex
act
or
coun
tin
g n
um
ber
s h
ave
an
amo
un
t o
f si
gn
ific
ant
fig
ure
s as
do
fu
nd
amen
tal
con
stan
ts
(nev
er t
o b
e co
nfu
sed
wit
h d
eriv
ed c
on
stan
ts)
Rep
ort
ing
th
e R
esu
lt o
f a
Ca
lcu
lati
on
to
th
e P
rop
erN
um
ber
of
Sig
nif
ica
nt
Fig
ure
s
Wh
en ×
and
,
the
term
wit
h t
he
lea
stn
um
ber
of
sig
nif
ica
nt
fig
ure
s(
leas
t ac
cura
te m
easu
rem
ent)
det
erm
ines
th
e n
um
ber
of
ma
xim
um
nu
mb
er o
f si
gn
ific
ant
fig
ure
s in
th
e an
swer
.(I
t’s
hel
pfu
l to
un
der
lin
e th
e d
igit
s in
the
leas
t si
gnif
ican
t n
um
ber
as
a re
min
der
.)
4.5
6×
1.4
= 6
.38
co
rrec
ted
6.4
Wh
en +
an
d (
), t
he
term
wit
h t
he
leas
t n
um
ber
of
dec
ima
l p
lace
s(
leas
t ac
cura
te m
easu
rem
ent)
det
erm
ines
th
e n
um
ber
of
sig
nif
ican
t fi
gu
res
in t
he
fin
al a
nsw
er.
12
.11
18
.0li
mit
ing
ter
m(o
nly
1 d
ecim
al p
lace
)
1.0
13
31
.12
3co
rrec
ted
31
.1(l
imit
s th
e o
ver
all
answ
er t
o o
nly
on
e d
ecim
al p
lace
)
pH
–th
e n
um
ber
of
sig
nif
ica
nt
fig
ure
s in
lea
st a
ccu
rate
mea
sure
men
td
eter
min
es n
um
ber
dec
ima
l
pla
ces
on
the
rep
ort
ed p
H(u
sual
ly e
xp
lain
ed i
n t
he
app
end
ix o
f y
ou
r te
xt)
Ro
un
din
g G
uid
elin
esfo
r th
e A
P E
xa
m a
nd
Th
is C
ou
rse:
Ro
un
d O
NL
Y a
t th
e en
d o
f al
l ca
lcu
lati
on
s(k
eep
th
e n
um
ber
s in
yo
ur
calc
ula
tor)
Ex
amin
eth
e si
gn
ific
ant
fig
ure
one
pla
ce b
eyo
nd
yo
ur
des
ired
nu
mb
er o
f si
gn
ific
ant
fig
ure
s.
IF>
5 r
ou
nd
up
; <
5 d
rop
th
e re
mai
nin
g d
igit
s.
Do
n’t
“d
ouble
ro
un
d”!
Ex
amp
le:
Th
e n
um
ber
7.3
48
rou
nd
ed t
o 2
SF
is
rep
ort
ed a
s 7
.3
In o
ther
wo
rds,
DO
NO
Tlo
ok
bey
on
d t
he
4 a
fter
th
e d
ecim
alan
d t
hin
k t
hat
th
e 8
roun
ds
the
4 u
p t
o a
fiv
e w
hic
h i
n t
urn
mak
es t
he
fin
al a
nsw
er 7
.4.
[Ev
en t
ho
ug
h y
ou
may
hav
e co
nn
ed a
teac
her
into
ro
un
din
g y
ou
r fi
nal
av
erag
e th
is w
ay b
efo
re!]
Ex
erci
se
2S
ign
ific
an
t F
igu
res
(SF
)
Giv
e th
e n
um
ber
of
sig
nif
ican
t fi
gu
res
for
each
of
the
foll
ow
ing
exp
erim
enta
l re
sult
s.
a. A
stu
den
t’s
extr
acti
on p
roce
du
re o
n a
sam
ple
of
tea
yie
lds
0.0
10
5 g
of
caff
ein
e.
b.
A c
hem
ist
reco
rds
a m
ass
of
0.0
50
08
0 g
in
an
an
aly
sis.
c. I
n a
n e
xp
erim
ent,
a s
pan
of
tim
e is
det
erm
ined
to
be
8.0
50
× 1
0s
.
a. th
ree;
b. fi
ve;
c.
fo
ur
Ch
emic
al F
ou
nd
atio
ns
5
Dim
ensi
on
al
An
aly
sis
Ex
am
ple
:C
on
sid
er a
str
aig
ht
pin
mea
suri
ng
2.8
5 c
m i
n l
eng
th.C
alcu
late
its
len
gth
in
in
ches
.
Sta
rt w
ith
a c
on
ver
sio
n f
acto
r su
ch a
s 2
.54
cm
= 1
in
ch
you
can
wri
te T
WO
Co
nv
ersi
on
fac
tors
: 1
in
2.5
4cm
or
2
.54
cm
1in
. W
hy
is
this
leg
al?
Bo
th q
uan
titi
es
rep
rese
nt
the
exac
t sa
me
“th
ing
” so
th
e co
nver
sion
fac
tor
is a
ctu
ally
eq
ual
to
“1
”.
To
co
nv
ert
the
len
gth
of
the
pin
fro
m c
m t
o i
nch
es,
sim
ply
mu
ltip
ly y
ou
r g
iven
qu
anti
ty b
y a
co
nver
sio
n
fact
or
yo
u e
ng
inee
r so
th
atit
“ca
nce
ls”
the
un
des
irab
leu
nit
an
d p
lace
sth
e d
esir
ed u
nit
wh
ere
you
wan
t it
.
Fo
r o
ur
exam
ple
, w
e w
ant
inch
es i
n t
he
nu
mer
ato
r so
ou
r n
um
eric
al a
nsw
er i
s n
ot
rep
ort
ed i
n r
ecip
roca
l
inch
es!
Th
us,
2.8
5cm
1in
2.5
4cm
= 1
.12
in
Let
’s p
ract
ice!
Ex
erci
se
3
A p
enci
l is
7.0
0 i
n.
lon
g. C
alcu
late
the
len
gth
in
cen
tim
eter
s?
17.8
cm
Ex
erci
se
4
Yo
u w
ant
to o
rder
a b
icycl
e w
ith
a 2
5.5
-in
. fr
ame,
bu
t th
e si
zes
in t
he
cata
log
are
giv
en o
nly
in
cen
tim
eter
s.
Wh
at s
ize
sho
uld
yo
u o
rder
?
6
4.8
in
Ex
erci
se
5
A s
tud
ent
has
en
tere
d a
10
.0-k
m r
un
. H
ow
lo
ng
is
the
run
in
mil
es?
We
hav
e k
ilo
met
ers,
wh
ich
we
wan
t to
ch
ang
e to
mil
es.
We
can
do
th
is b
y t
he
foll
ow
ing
ro
ute
:
kil
om
eter
s
met
ers
yar
ds
m
iles
To
pro
ceed
in
th
is w
ay, w
e n
eed
th
e fo
llo
win
g e
qu
ival
ence
sta
tem
ents
(con
ver
sio
n f
acto
rs):
1 k
m =
10
00
m
1 m
=
1.0
94
yd
17
60
yd
= 1
mi
6
.22 m
i
Ch
emic
al F
ou
nd
atio
ns
6
Tem
per
atu
re
I su
spec
t y
ou
are
aw
are
ther
e ar
e th
ree
tem
per
atu
re s
cale
sco
mm
on
ly i
n u
se t
od
ay.
A c
om
par
iso
n f
oll
ow
s:
No
tice
a d
egre
e o
f te
mp
erat
ure
ch
ange
on
th
e C
elsi
us
scal
e re
pre
sen
ts t
he
sam
e q
uan
tity
of
chan
ge
on
th
e K
elv
in
scal
e.
Ex
erci
se
6
Th
e sp
eed
lim
it o
n m
any
hig
hw
ays
in t
he
Un
ited
Sta
tes
is 5
5 m
i/h
. W
hat
nu
mb
er w
ou
ld b
e p
ost
ed i
f ex
pre
ssed
in k
ilo
met
ers
per
ho
ur?
88
km
/h
Ex
erci
se
7
A J
apan
ese
car
is a
dv
erti
sed
as h
avin
g a
fu
el e
con
om
y o
f 1
5 k
m/L
. C
on
ver
t th
is r
atin
g t
o m
iles
per
gal
lon
.
35
mi
/ga
l
Ch
emic
al F
ou
nd
atio
ns
7
Den
sity
Cla
ssif
icati
on
of
Ma
tter
Sta
tes
of
Ma
tter
(mo
stly
a v
oca
bu
lary
les
son
)
Be
ver
y, v
ery
cle
ar
that
cha
ng
es o
f st
ate
in
vo
lve
alt
erin
g I
MF
s n
ot
alt
erin
g a
ctu
al
chem
ical
bo
nd
s!!
soli
d–
rig
id;
def
init
e sh
ape
and
vo
lum
e; m
ole
cule
s cl
ose
tog
eth
er v
ibra
ting
ab
ou
t fi
xed
po
ints
virt
ua
lly
inco
mp
ress
ible
liq
uid
–d
efin
ite
volu
me
bu
t ta
kes
on
th
e sh
ape
of
the
con
tain
er;
mo
lecu
les
stil
l vi
bra
te b
ut
als
o h
ave
rota
tio
nal
an
d t
ransl
ati
on
al
mo
tio
n a
nd
ca
n s
lide
past
on
e an
oth
er B
UT
are
sti
ll c
lose
tog
eth
er
slig
htl
y co
mpre
ssib
le
ga
s–
no
def
init
e v
olu
me
and
tak
es o
n t
he
shap
e o
f th
e co
nta
iner
; m
ole
cule
s vi
bra
te,
rota
te a
nd
tra
nsl
ate
an
d a
re i
nd
epen
den
t of
each
oth
er
VE
RY
fa
r ap
art
hig
hly
com
pre
ssib
le
-v
ap
or
–th
e g
as p
has
e o
f a
sub
stan
ce t
hat
is
norm
ally
a s
oli
d o
r li
quid
at
roo
m t
emp
erat
ure
-fl
uid
–th
at w
hic
h c
an f
low
; g
ases
an
d l
iqu
ids M
ixtu
res
–ca
n b
e p
hy
sica
lly
sep
arat
ed
-h
om
og
eneo
us
–h
ave
vis
ibly
ind
isti
ng
uis
hab
le
par
ts,
solu
tio
ns
incl
udin
g a
ir
-h
eter
ogen
eou
s–
hav
e v
isib
ly d
isti
ng
uis
hab
le p
arts
-m
ean
s o
f p
hy
sica
l se
par
atio
n i
ncl
ude:
fil
teri
ng
,
frac
tio
nal
cry
stal
liza
tion
, d
isti
llat
ion
,
chro
mat
og
rap
hy
Den
sity
=
vo
lum
e
mas
s
Ex
erci
se
8D
eter
min
ing
Den
sity
A c
hem
ist,
try
ing
to
id
enti
fy t
he
mai
n c
om
po
nen
t o
f a
com
pac
t d
isc
clea
nin
g f
luid
, d
eter
min
esth
at 2
5.0
0 c
m3
of
the
sub
stan
ce h
as a
mas
s o
f 1
9.6
25
g
at 2
0C
. U
se t
he
info
rmat
ion
in
th
e ta
ble
bel
ow
to
id
enti
fy w
hic
h
sub
stan
ce m
ay s
erv
e as
th
e m
ain
co
mp
on
ent
of
the
clea
nin
g f
luid
.Ju
stif
y y
ou
r an
swer
wit
h a
cal
cula
tio
n.
Co
mp
ou
nd
Den
sity
(g/c
m3)
at 2
0C
Ch
loro
form
1.4
92
Die
thy
l et
her
0.7
14
Eth
ano
l0
.78
9
Isop
rop
yl
alco
ho
l0
.78
5
To
luen
e0
.86
7
Den
sity
=
0.7
850
g
/cm
3is
op
rop
yl
alc
oh
ol
Ch
emic
al F
ou
nd
atio
ns
8
Pap
er C
hro
mat
og
rap
hy
:
Dis
till
atio
n:
Pap
er c
hro
mat
ogra
ph o
f in
k. (a
) A
lin
e of
the
mix
ture
to b
e se
par
ate
ispla
ced a
t one
end o
f a
shee
t of
poro
us
pap
er. (b
) T
he
pap
er a
cts
as
a w
ick t
o d
raw
up
the
liquid
. (c
) T
he
com
ponen
t w
ith t
he
wea
kes
t
att
ract
ion f
or
the
pap
er t
ravel
s fa
ster
than
those
that
cli
ng t
o t
he
pap
er.
Pu
re s
ub
sta
nce
s–
com
po
un
ds
lik
e w
ater
, ca
rbo
n d
iox
ide
etc.
an
del
emen
ts.
Co
mp
ou
nd
s ca
n b
e se
par
ated
into
ele
men
ts b
y c
hem
ical
mea
ns
-el
ectr
oly
sis
is a
co
mm
on
ch
emic
al m
eth
od
fo
r se
par
atin
g c
om
po
un
ds
into
elem
ents
-el
emen
ts c
an b
e b
rok
en d
ow
n i
nto
ato
ms
wh
ich
can
be
furt
her
bro
ken
dow
n i
nto
-n
ucl
ei a
nd
ele
ctro
ns
-p
+,n
0an
d e
-
-q
uar
ks
Ele
ctro
lysi
s is
an
ex
amp
le o
f a
chem
ical
ch
ang
e. I
n t
his
ap
par
atu
s,
wat
er i
s d
eco
mp
ose
d t
o h
yd
rog
en g
as
(fil
lin
g t
he
red
bal
loo
n)
and
Ox
yg
en
gas
(fi
llin
g t
he
blu
e b
allo
on
).
Ch
emic
al F
ou
nd
atio
ns
9
AP
* C
hem
istr
y
AT
OM
S, M
OL
EC
UL
ES
& I
ON
S
This
is
the
hig
hes
t honor
giv
en b
y t
he
Am
eric
an
Chem
ical
Soci
ety.
Pri
estl
ydis
cover
ed
oxygen
. B
en F
rankli
n g
ot
him
inte
rest
ed i
n
elec
tric
ity a
nd h
e
ob
serv
ed g
rap
hit
e
conduct
s an
ele
ctri
c
curr
ent.
P
oli
tics
forc
ed
him
out
of
Engla
nd a
nd
he
die
d i
n t
he
US
in 1
804.
The
bac
k s
ide,
pic
ture
d
bel
ow
was
giv
en t
o L
inus
Pau
ling i
n 1
984.
Pau
ling
was
the
only
per
son t
o
win
Nob
el P
rize
s in
TW
O
Dif
fere
nt
fiel
ds:
Chem
istr
y a
nd P
eace
.
TH
E E
AR
LY
HIS
TO
RY
OF
CH
EM
IST
RY
1,0
00
B.C
.—p
roce
ssin
g o
f o
res
to p
rod
uce
met
als
for
wea
po
ns
and
orn
amen
ts;
use
of
emb
alm
ing
flu
ids
40
0 B
.C.—
Gre
eks—
pro
po
sed
all
mat
ter
was
mak
e up
of
4 “
elem
ents
”:
fire
, ea
rth
, w
ater
an
d a
ir
Dem
ocr
itu
s—fi
rst
to u
se t
he
term
ato
mos
to d
escr
ibe
the
ult
imat
e, s
mal
lest
par
ticl
es o
f m
atte
r
Nex
t 2
,00
0 y
ears
—a
lch
emy—
a p
seu
do
scie
nce
wh
ere
peo
ple
so
ug
ht
totu
rn
met
als
into
go
ld.
Mu
ch w
as l
earn
ed f
rom
th
e p
leth
ora
of
mis
takes
alch
emis
ts m
ade.
16
thce
ntu
ry—
Geo
rg B
auer
, G
erm
an ,
ref
ined
th
e p
roce
ss o
f ex
trac
tin
g
met
als
fro
m o
res
&
Par
acel
sus,
Sw
iss,
use
d m
iner
als
for
med
icin
al
app
lica
tio
ns
Rob
ert
Bo
yle
, E
ng
lish
—fi
rst
“ch
emis
t” t
o p
erfo
rm q
ua
nti
tati
ve
exp
erim
ents
of
pre
ssu
re v
ersu
s v
olu
me.
D
evel
op
ed a
wo
rkin
g d
efin
itio
n f
or
“ele
men
ts”.
17
th&
18
thC
entu
ries
—G
eorg
Sta
hl,
Ger
man
—su
gg
este
d “
ph
log
isto
n”
flo
wed
OU
T o
f b
urn
ing
mat
eria
l.
An
ob
ject
sto
pp
ed b
urn
ing
in
a c
lose
d
con
tain
er s
ince
th
e ai
r w
as “
satu
rate
d w
ith p
hlo
gis
ton
”
Jose
ph
Pri
estl
ey,
En
gli
sh—
dis
cov
ered
ox
yg
en w
hic
h w
as o
rig
inal
ly c
alle
d
“dep
hlo
gis
tica
ted
air
”
FU
ND
AM
EN
TA
L C
HE
MIC
AL
LA
WS
late
18
thC
entu
ry—
Co
mb
ust
ion
stu
die
d e
xte
nsi
vel
y
CO
2, N
2,
H2
and
O2
dis
cov
ered
list
of
elem
ents
co
nti
nu
ed t
o g
row
An
tio
ne
Lav
ois
ier,
Fre
nch
—ex
pla
ined
th
e tr
ue
nat
ure
of
com
bu
stio
n—
pub
lish
ed t
he
firs
t m
od
ern
chem
istr
y t
extb
oo
k A
ND
sta
ted
th
e L
aw o
f
Co
nse
rvat
ion
of
Mas
s.
Th
e F
ren
ch R
evo
luti
on
bro
ke
ou
t th
e sa
me
yea
r h
is
tex
t w
as p
ub
lish
ed.
He
on
ce c
oll
ecte
d t
axes
fo
r th
e g
ov
ern
men
t an
d w
as
exec
ute
d w
ith
a g
uil
loti
ne
as a
n e
nem
y o
f th
e p
eop
le i
n 1
79
4.
He
was
th
e
firs
t to
in
sist
on
qu
an
tita
tive
exp
erim
enta
tio
n.
TH
E L
AW
OF
CO
NS
ER
VA
TIO
N O
F M
AS
S:
Mass
is
nei
ther
cre
ate
d n
or
des
troye
d.
*A
P i
s a
regis
tere
d t
radem
ark o
f th
e C
oll
ege
Boar
d,
whic
h w
as n
ot
involv
ed i
n t
he
pro
duct
ion o
f th
is p
roduct
.
© 2
013
by
Ren
é M
cCorm
ick.
All
rig
hts
res
erved
.
18
08
--Jo
hn
Dal
ton
sta
ted
th
e L
aw o
f D
efin
ite
pro
po
rtio
ns.
He
late
r w
ent
on
to
dev
elop
th
e A
tom
ic T
heo
ry o
f M
atte
r.
TH
E L
AW
OF
DE
FIN
ITE
PR
OP
OR
TIO
NS
:
A g
iven
com
po
un
d a
lways
con
tain
s ex
act
ly t
he
sam
e p
rop
ort
ion
s of
elem
ents
by
mass
.
TH
E L
AW
OF
MU
LT
IPL
E P
RO
PO
RT
ION
S:
Wh
en t
wo e
lem
ents
co
mb
ine
to f
orm
a s
erie
s of
com
po
un
ds,
th
e ra
tios
of
the
mass
es o
f th
e se
con
d e
lem
ent
tha
t co
mbin
e w
ith
1 g
ram
of
the
firs
t el
emen
t ca
n a
lways
be
red
uce
d t
o s
ma
ll w
hole
nu
mb
ers.
Dal
ton
co
nsi
der
ed c
om
po
un
ds
of
carb
on
an
d o
xy
gen
an
d d
eter
min
ed:
Mass
of
Ox
ygen
th
at
com
bin
es w
ith
1 g
ram
of
C
Co
mp
ou
nd
I1
.33
g
Co
mp
ou
nd
II
2.6
6 g
Th
eref
ore
,C
om
po
un
d I
may
be
CO
wh
ile
Co
mp
ou
nd
II
may
be
CO
2.
Ex
erci
se 1
Illu
stra
tin
g t
he
La
w o
f M
ult
iple
Pro
po
rtio
ns
Th
e fo
llo
win
g d
ata
wer
e co
llec
ted
fo
r se
ver
al c
om
po
un
ds
of
nit
rog
en a
nd
ox
yg
en:
Mass
of
Nit
rog
en T
ha
t C
om
bin
es W
ith
1
g
of
Oxy
gen
Co
mp
ou
nd
A
1.7
500
g
Co
mp
ou
nd
B
0.8
75
0
g
Co
mp
ou
nd
C
0.4
37
5
g
Sh
ow
ho
w t
hes
e d
ata
illu
stra
te t
he
law
of
mu
ltip
le p
rop
ort
ion
s.
A=
1.7
500
= 2
B
0
.8750
1
B=
0.8
750
= 2
C
0.4
375
1
A=
1.7
50
= 4
C
0.4
375
1
*A
P i
s a
regis
tere
d t
radem
ark o
f th
e C
oll
ege
Boar
d,
whic
h w
as n
ot
involv
ed i
n t
he
pro
duct
ion o
f th
is p
roduct
.
© 2
013
by
Ren
é M
cCorm
ick.
All
rig
hts
res
erved
.
DA
LT
ON
’S A
TO
MIC
TH
EO
RY
Po
stu
late
s o
f D
alt
on
’s A
TO
MIC
TH
EO
RY
OF
MA
TT
ER
: (
bas
ed o
n k
no
wle
dg
e a
t th
at
tim
e)
1.
All
mat
ter
is m
ade
of
ato
ms.
T
hes
e in
div
isib
le a
nd
in
des
tru
ctib
le o
bje
cts
are
the
ult
imat
e ch
emic
al
par
ticl
es.
2.
All
th
e at
om
s o
f a
giv
en e
lem
ent
are
iden
tica
l, i
n b
oth
wei
gh
t an
d c
hem
ical
pro
per
ties
. H
ow
ever
, at
om
s o
f
dif
fere
nt
elem
ents
hav
e dif
fere
nt
wei
ghts
an
d d
iffe
ren
t ch
emic
al p
rop
erti
es.
3.
Co
mp
ou
nd
sar
e fo
rmed
by
th
e co
mb
inat
ion
of
dif
fere
nt
ato
ms
in t
he
rati
o o
f sm
all
wh
ole
nu
mb
ers.
4.
Ach
emic
al
rea
ctio
nin
vo
lves
on
ly t
he
com
bin
atio
n,
sep
arat
ion
, o
r re
arra
ng
emen
t o
f at
om
s; a
tom
s ar
e
nei
ther
cre
ated
no
r d
estr
oy
ed i
n t
he
cou
rse
of
ord
inar
y c
hem
ical
rea
ctio
ns.
**
TW
O M
OD
IFIC
AT
ION
S H
AV
E B
EE
N M
AD
E T
O D
AL
TO
N’S
TH
EO
RY
:
1.
Su
ba
tom
ic p
art
icle
s w
ere
dis
cove
red
.B
et y
ou
ca
n n
am
e th
em!
2.
Iso
top
es w
ere
dis
cove
red.B
et y
ou
ca
n d
efin
e “
iso
top
e” a
s w
ell!
18
09
Jo
sep
h G
ay-L
uss
ac, F
ren
ch—
per
form
ed e
xp
erim
ents
[at
co
nst
ant
tem
per
atu
re a
nd
pre
ssure
] an
d
mea
sure
d v
olu
mes
of
gas
es t
hat
rea
cted
wit
h e
ach
oth
er.
18
11
Av
og
adro
, It
alia
n—
pro
po
sed
his
hyp
oth
esis
reg
ard
ing
Gay
-Lu
ssac
’s w
ork
[an
d y
ou
th
ou
gh
t h
e
was
ju
st f
amo
us
for
6.0
2 ×
10
23]
He
was
bas
ical
ly i
gn
ore
d,
so 5
0 y
ears
of
con
fusi
on
fo
llo
wed
.
AV
OG
AD
RO
’S H
YP
OT
HE
SIS
:
At
the
sam
e te
mp
era
ture
an
d p
ress
ure
, eq
ua
l vo
lum
es o
f d
iffe
ren
tg
ase
s co
nta
in t
he
sam
e n
um
ber
of
pa
rtic
les.
Ato
ms,
Mole
cule
s an
d I
ons
3
EA
RL
Y E
XP
ER
IME
NT
S T
O C
HA
RA
TE
RIZ
E T
HE
AT
OM
Bas
ed o
n t
he
wo
rk o
f D
alto
n,
Gay
-Lu
ssac
, A
vo
gad
ro,
& o
ther
s, c
hem
istr
y w
as b
egin
nin
g t
o m
ake
sen
se [
even
if
YO
Ud
isag
ree!
] an
d t
he
con
cep
t o
f th
e at
om
was
cle
arly
a g
oo
d i
dea
!
TH
E E
LE
CT
RO
N
J.J.
Th
om
son
, E
ng
lish
(1
89
8-1
90
3)—
fou
nd
th
at w
hen
hig
h v
olt
age
was
ap
pli
edto
an
ev
acu
ated
tub
e, a
“ray
” h
e ca
lled
a c
ath
od
e ra
y [
sin
ce i
t em
anat
ed f
rom
th
e (
) el
ectr
od
e o
r ca
tho
de
when
YO
U a
pp
ly a
vo
ltag
e ac
ross
it]
was
pro
du
ced
.
oT
he
ray
was
pro
du
ced
at
the
()
elec
tro
de
oR
epel
led
by
th
e (
) p
ole
of
an a
pp
lied
ele
ctri
c fi
eld
, E
oH
e p
ost
ula
ted
th
e ra
y w
as a
str
eam
of
NE
GA
TIV
E p
arti
cles
no
w c
alle
d e
lect
ron
s, e
He
then
mea
sure
d t
he
def
lect
ion
of
bea
ms
of
eto
det
erm
ine
the
cha
rge-
to-m
ass
ra
tio
eis
ch
arg
e o
n e
lect
ron
in
Co
ulo
mb
s, (
C)
and
mis
its
mas
s.
Th
om
son
dis
cov
ered
th
at h
e co
uld
rep
eat
this
def
lect
ion
an
d
calc
ula
tio
n u
sin
g e
lect
rod
es o
f d
iffe
ren
t m
etal
sal
l m
etal
s
con
tain
ed e
lect
ron
s an
d A
LL
AT
OM
S c
on
tain
ed e
lect
ron
s
Fu
rth
erm
ore
, al
l at
om
s w
ere
neu
tral
th
ere
must
be
som
e (+
) ch
arg
e
wit
hin
th
e at
om
an
d t
he
“plu
m p
ud
din
g”
mo
del
was
bo
rn.
Lo
rd
Kel
vin
may
hav
e p
lay
ed a
ro
le i
n t
he
dev
elop
men
t o
f th
is m
od
el.
[Th
e B
riti
sh c
all
ever
yd
esse
rt “
pu
dd
ing
”—w
e’d
cal
l it
rai
sin
bre
ad
wh
ere
the
rais
ins
wer
e th
e el
ectr
on
s ra
nd
om
ly d
istr
ibu
ted
th
rou
gh
ou
t th
e +
bre
ad]
19
09
Rob
ert
Mil
lik
an,
Am
eric
an—
Un
iver
sity
of
Ch
icag
o,
spra
yed
ch
arg
ed
oil
dro
ps
into
a c
ham
ber
.N
ext,
he
hal
ted
th
eir
fall
du
e to
gra
vit
y b
y
adju
stin
g t
he
vo
ltag
e ac
ross
2 c
har
ged
pla
tes.
N
ow
th
e v
olt
age
nee
ded
to
hal
t
the
fall
an
d t
he
mas
s o
f th
e o
il d
rop
can
be
use
d t
o c
alcu
late
th
e ch
arg
e o
n t
he
oil
dro
p w
hic
h i
s a
wh
ole
nu
mb
er m
ult
iple
of
the
elec
tro
n c
har
ge.
Mas
s o
f e
= 9
.11
×1
03
1k
g.
81.7
610
eC
mg
Ato
ms,
Mole
cule
s an
d I
ons
4
RA
DIO
AC
TIV
ITY
Hen
ri B
ecq
uer
el,
Fre
nch
—fo
un
d o
ut
qu
ite
by
acc
iden
t [s
eren
dip
ity
] th
at a
pie
ce o
f m
iner
al c
on
tain
ing
ura
niu
m c
ou
ld p
rod
uce
its
im
age
on
a p
ho
tog
rap
hic
pla
te i
n t
he
abse
nce
of
lig
ht.
H
e ca
lled
th
is
rad
ioa
ctiv
ity a
nd
att
rib
ute
d i
t to
a s
po
nta
neo
us
emis
sio
n o
f ra
dia
tio
n b
y t
he
ura
niu
m i
n t
he
min
eral
sam
ple
.
TH
RE
E t
yp
es o
f ra
dio
acti
ve
emis
sio
n:
oa
lph
a,
--eq
uiv
alen
t to
a h
eliu
m n
ucl
eus;
th
e la
rges
t p
arti
cle
radio
acti
ve
par
ticl
e em
itte
d;
73
00
tim
es t
he
mas
s o
f an
ele
ctro
n.
H
e4 2
Sin
ce t
hes
e ar
e la
rger
th
at t
he
rest
, ea
rly
ato
mic
stu
die
s o
ften
in
vo
lved
th
em.
ob
eta
, --
a h
igh
sp
eed
ele
ctro
n.
0 1O
Re
0 1
og
am
ma
, --
pu
re e
ner
gy
, n
o p
arti
cles
at
all!
M
ost
pen
etra
tin
g,
ther
efo
re,
mo
st d
ang
ero
us.
TH
E N
UC
LE
AR
AT
OM
19
11
Ern
est
Ru
ther
ford
, E
ng
lan
d—
A p
ion
eer
in r
adio
acti
ve
stu
die
s, h
e ca
rrie
d o
ut
exp
erim
ents
to
tes
t
Th
om
son
’s p
lum
pu
dd
ing
mo
del
.
oD
irec
ted
par
ticl
es a
t a
thin
sh
eet
of
go
ld f
oil
. H
e th
ou
gh
t th
at i
f T
ho
mso
n w
as c
orr
ect,
th
en t
he
mas
siv
e p
arti
cles
wo
uld
bla
st t
hro
ug
h t
he
thin
fo
il l
ike
“can
no
nb
alls
th
rou
gh
gau
ze”.
[H
e ac
tual
ly
had
a p
air
of
gra
du
ate
stu
den
ts G
eig
er &
Mar
sden
do
th
e fi
rst
rou
nd
s o
f ex
per
imen
ts.]
H
e ex
pec
ted
the
par
ticl
es t
o p
ass
thro
ug
h w
ith
min
or
and
occ
asio
nal
def
lect
ion
s.
oT
he
resu
lts
wer
e as
tou
nd
ing
[p
oo
r G
eig
er a
nd
Mar
sden
fir
st s
uff
ered
Ru
ther
ford
’s w
rath
an
d w
ere
told
to
try
ag
ain
—si
nce
th
is c
ou
ldn
’t b
e!].
Mo
st o
f th
e p
arti
cles
did
pas
s st
raig
ht
thro
ug
h,
BU
T m
any
wer
e d
efle
cted
at
LA
RG
E
ang
les
and
so
me
even
RE
FL
EC
TE
D!
Ru
ther
ford
sta
ted
th
at w
as l
ike
“sh
oo
tin
g a
ho
wit
zer
at a
pie
ce o
f ti
ssu
e p
aper
an
d h
avin
g t
he
shel
l re
flec
ted
bac
k”
He
kn
ewth
ep
lum
pu
dd
ing
mo
del
co
uld
no
t b
e co
rrec
t!
Th
ose
par
ticl
es w
ith
lar
ge
def
lect
ion
ang
les
had
a “
clo
se e
nco
unte
r” w
ith
th
e
den
se p
osi
tiv
e ce
nte
r o
f th
e at
om
Th
ose
th
at w
ere
refl
ecte
d h
ad a
“d
irec
t
hit
”
He
con
ceiv
ed t
he
nu
clea
r a
tom
; th
at
wit
h a
den
se (
+)
core
or
nu
cleu
s.
Th
is c
ente
r co
nta
ins
mo
st o
f th
e m
ass
of
the
ato
m w
hil
e th
e re
mai
nd
er o
f th
e at
om
is e
mp
ty s
pac
e!
Ato
ms,
Mole
cule
s an
d I
ons
5
Par
ticl
eM
ass
Char
ge
e9.1
1 ×
10
31
1
p+
1.6
7 ×
10
27
1+
n0
1.6
7 ×
10
27
None
TH
E M
OD
ER
N V
IEW
OF
AT
OM
IC S
TR
UC
TU
RE
: A
N I
NT
RO
DU
CT
ION
EL
EM
EN
TS
All
mat
ter
com
po
sed
of
on
ly o
ne
typ
e o
f at
om
is
an e
lem
ent.
T
her
e ar
e 9
2 n
atu
rall
y o
ccu
rrin
g,
all
oth
ers
are
ma
nm
ade.
AT
OM
S
ato
m--
the
smal
lest
par
ticl
e o
f an
ele
men
t th
at r
etai
ns
the
chem
ical
pro
per
ties
of
that
ele
men
t.
nu
cleu
s--c
on
tain
s th
e p
roto
ns
and
th
e n
eutr
on
s; t
he
elec
tro
ns
are
loca
ted
ou
tsid
e th
e n
ucl
eus.
D
iam
eter
= 1
01
3cm
. T
he
elec
tro
ns
are
loca
ted
10
8cm
fro
m t
he
nu
cleu
s.
A m
ass
of
nu
clea
r m
ater
ial
the
size
of
a p
ea
wo
uld
wei
gh
25
0 m
illi
on
to
ns!
V
ery
den
se!
-p
roto
n--
po
siti
ve
char
ge,
res
po
nsi
ble
fo
r th
e id
enti
ty o
f th
e
elem
ent,
def
ines
ato
mic
nu
mb
er
-n
eutr
on
--n
o c
har
ge,
sam
e si
ze &
mas
s as
a p
roto
n,
resp
on
sib
le
for
iso
top
es,
alte
rs a
tom
ic m
ass
nu
mb
er
-el
ectr
on
--n
egat
ive
char
ge,
sam
e si
ze a
s a
pro
ton
or
neu
tro
n,
BU
T 1
/2,0
00
th
e m
ass
of
a p
roto
n o
r n
eutr
on
, re
spo
nsi
ble
fo
r
bo
nd
ing
, h
ence
rea
ctio
ns
and
io
niz
atio
ns,
eas
ily
ad
ded
or
rem
ov
ed.
ato
mic
nu
mb
er(Z
)--T
he
nu
mb
er o
f p
+ i
n a
n a
tom
. A
ll a
tom
s o
f th
e
sam
eel
emen
t hav
e th
e sa
me
nu
mb
ero
f p
+.
ma
ss n
um
ber
(A)-
-Th
e su
m o
f th
e n
um
ber
of
neu
tro
ns
and
p+
fo
r an
ato
m.
A d
iffe
ren
t m
ass
nu
mb
er d
oes
no
tm
ean
a d
iffe
ren
t el
emen
t--j
ust
sig
nif
ies
an i
soto
pe.
mas
s n
um
ber
elem
ent
sym
bo
l
ato
mic
nu
mb
er
Th
e ac
tual
mas
s is
no
t an
in
teg
ral
nu
mb
er!
ma
ss d
efec
t--c
ause
s th
is a
nd
is
rela
ted
to
th
e en
erg
y
bin
din
g t
he
par
ticl
es o
f th
e n
ucl
eus
tog
eth
er.
Ex
erci
se
2W
riti
ng
th
e S
ym
bo
ls f
or
Ato
ms
Wri
te t
he
sym
bo
l fo
r th
e at
om
th
at h
as a
n a
tom
ic n
um
ber
of
9 a
nd
a m
ass
nu
mb
er o
f 1
9.
Ho
w m
any
ele
ctro
ns
and
ho
w m
any
neu
tro
ns
do
es t
his
ato
m h
ave?
F;
9 e
lect
ron
s a
nd
10 n
eutr
on
s
A Z
Ato
ms,
Mole
cule
s an
d I
ons
6
ISO
TO
PE
S
iso
top
es--
ato
ms
hav
ing
th
e sa
me
ato
mic
nu
mb
er (
# o
fp
+)
bu
t a
dif
fere
nt
nu
mb
er o
f n
eutr
on
s
mo
st e
lem
ents
hav
e at
lea
st t
wo
sta
ble
iso
top
es,
ther
e
are
ver
y f
ew w
ith
on
ly o
ne
stab
le i
soto
pe
(Al,
F,
P)
Hy
dro
gen
’s i
soto
pes
are
so
im
po
rtan
t th
ey h
ave
spec
ial
nam
es:
-0
neu
tro
ns
hy
dro
gen
-1
neu
tro
n
deu
teri
um
-2
neu
tro
ns
trit
ium
MO
LE
CU
LE
S A
ND
IO
NS
Ele
ctro
ns
are
the
on
ly s
ub
ato
mic
par
ticl
es i
nv
olv
ed i
nb
on
din
g a
nd
ch
emic
al r
eact
ivit
y.
Ch
emic
al
bo
nd
s—fo
rces
th
at h
old
ato
ms
tog
eth
er
Co
va
len
t b
on
ds—
ato
ms
shar
e el
ectr
on
s an
d m
ake
mo
lecu
les
[in
dep
end
ent
un
its]
; H
2,
CO
2,
H2O
, N
H3,
O2,
CH
4to
nam
e a
few
.
mo
lecu
le--
smal
lest
un
it o
f a
com
po
un
d t
hat
ret
ain
s th
e ch
em.
char
acte
rist
ics
of
the
com
po
un
d;
char
acte
rist
ics
of
the
con
stit
uen
t el
emen
ts a
re l
ost
.
mo
lecu
lar
form
ula
--u
ses
sym
bo
ls a
nd
sub
scri
pts
to
rep
rese
nt
the
com
po
siti
on
of
the
mo
lecu
le.
(Str
icte
st s
ense
--co
val
entl
y b
on
ded
)
stru
ctu
ral
form
ula
—b
on
ds
are
sho
wn
by
lin
es [
rep
rese
nti
ng
sh
ared
ep
airs
]; m
ay N
OT
in
dic
ate
shap
e
H O
H
O
HH
ion
s--f
orm
ed w
hen
ele
ctro
ns
are
lost
or
gai
ned
in o
rdin
ary
ch
em.
reac
tio
ns;
dra
mat
ic c
han
ge
in s
ize
(mo
re a
bo
ut
that
sh
ort
ly)
cati
on
s--(
+)
ion
s; o
ften
met
als
sin
ce m
etal
s lo
seel
ectr
on
s to
bec
om
e
posi
tive
lych
arg
ed
an
ion
s--(
) io
ns;
oft
en n
on
met
als
sin
ce n
on
met
als
ga
inel
ectr
ons
to b
eco
me
neg
ati
vely
char
ged
po
lya
tom
ic i
on
s--u
nit
s o
f at
om
s b
ehav
ing
as
on
e en
tity
It
’s w
ort
h m
emo
rizi
ng
9 p
oly
ato
mic
ion
s +
3 p
atte
rns.
(se
par
ate
han
do
ut)
ion
ic s
oli
ds—
Ele
ctro
stat
ic f
orc
es h
old
io
ns
tog
eth
er.
We
can
cal
cula
te t
he
mag
nit
ud
e o
f th
em
usi
ng
Co
ulo
mb
’s L
aw.
Wh
en t
hes
e el
ectr
ost
atic
att
ract
ion
s ar
e st
ron
g,
the
ion
s ar
e h
eld
to
get
her
tig
htl
y a
nd
are
clo
se t
og
eth
er
soli
ds.
Ad
dit
ion
ally
, th
e st
ron
ger
th
e C
ou
lom
bic
fo
rce,
Fc,
the
hig
her
th
e m
elti
ng
po
int.
Co
ulo
mb
’sL
aw:
12
2c
Fd
or
12
2c
Fk
d
Ato
ms,
Mole
cule
s an
d I
ons
7
Curr
ent
Nam
eO
rigin
al N
ame
(oft
en L
atin
)
Sym
bol
Anti
mony
Sti
biu
mS
b
Copp
erC
up
rum
Cu
Iron
Fer
rum
Fe
Lea
dP
lum
bum
Pb
Mer
cury
Hydra
rgyru
mH
g
Pota
ssiu
mK
aliu
mK
Sil
ver
Arg
entu
mA
g
Sodiu
mN
atri
um
Na
Tin
Sta
nnum
Sn
Tungst
enW
olf
ram
W
AN
IN
TR
OD
UC
TIO
N T
O T
HE
PE
RIO
DIC
TA
BL
E
Ato
mic
nu
mb
er =
nu
mb
er o
f p
roto
ns
and
is
wri
tten
ab
ov
e
each
sy
mb
ol
met
als
—m
alle
able
, d
uct
ile
& h
ave
lust
er;
mo
st o
f th
e
elem
ents
are
met
als—
exis
t as
cat
ion
s in
a “
sea
of
elec
tron
s” w
hic
h a
cco
un
ts f
or
thei
r ex
cell
ent
con
du
ctiv
e
pro
per
ties
; fo
rm o
xid
es [
tarn
ish
] re
adil
y a
nd
fo
rm
PO
SIT
IVE
io
ns
[cat
ion
s].
Wh
y m
ust
so
me
hav
e su
ch
go
ofy
sy
mb
ols
?
gro
up
s o
r fa
mil
ies-
-ver
tica
l co
lum
ns;
hav
e si
mil
ar
ph
ysi
cal
and
ch
emic
al p
rop
erti
es (
bas
ed o
n s
imil
ar e
lect
ron
con
fig
ura
tio
ns!
!)
gro
up
A—
Rep
rese
nta
tiv
e el
emen
ts
gro
up
B--
tran
siti
on
ele
men
ts;
all
met
als;
hav
e n
um
ero
us
ox
idat
ion
/val
ence
sta
tes
per
iod
s--h
ori
zon
tal
row
s; p
rog
ress
fro
m m
etal
s to
met
allo
ids
[eit
her
sid
e o
f th
e b
lack
“st
air
step
” li
ne
abo
ve
that
sep
arat
es m
etal
s fr
om
no
nm
etal
s] t
o n
on
met
als
ME
MO
RIZ
E:
1.
AL
KA
LI
ME
TA
LS
—1
A o
r IA
2.
AL
KA
LIN
E E
AR
TH
ME
TA
LS
—2
Ao
r II
A
3.
HA
LO
GE
NS
—7
Ao
r V
IIA
4.
NO
BL
E (
RA
RE
) G
AS
SE
S—
8A
or
VII
IA
Ato
ms,
Mole
cule
s an
d I
ons
8
NA
MIN
G S
IMP
LE
CO
MP
OU
ND
S
BIN
AR
Y I
ON
IC C
OM
PO
UN
DS
Nam
ing
(+
)io
ns:
usu
ally
met
als
mo
nat
om
ic,
met
al,
cati
on
si
mp
ly t
he
nam
e o
f th
e m
etal
fro
m w
hic
h i
t is
der
ived
. A
l3+
is t
he
alu
min
um
io
n;
tran
siti
on
met
als
form
mo
re t
ha
n o
ne
ion
; R
om
an N
um
eral
s (i
n)
foll
ow
th
e io
n’s
nam
e,
they
are
yo
ur
frie
nd
—th
ey t
ell
yo
u w
hic
h c
har
ge
is o
nth
at p
arti
cula
r io
n C
u2
+is
co
pp
er(I
I);
Mer
cury
(I)
is a
n e
xce
pti
on
it i
s H
g2
2+
two
Hg
+ass
oci
ate
d t
og
eth
eral
so,
rem
emb
er H
g i
s a
met
al t
hat
is
a li
qu
id a
t ro
om
tem
per
atu
re.
(Yea
h,
the
no
sp
ace
thin
g b
etw
een
th
e io
n’s
nam
e an
d
(Ro
man
Nu
mer
al)
loo
ks
stra
ng
e, b
ut
it i
s th
e co
rrec
t w
ay t
o d
o i
t.It
’s c
alle
d t
he
Sto
ck s
yst
em d
evel
op
ed
by
th
e G
erm
an c
hem
ist
Alf
red
Sto
ck a
nd
fir
st p
ub
lish
ed i
n 1
91
6.)
NH
4+
isam
mo
niu
m
NO
RO
MA
N N
UM
ER
AL
IS
US
ED
WIT
H s
ilv
er,
cad
miu
m a
nd
zin
c. W
hy
no
t?
Th
ey o
nly
mak
e o
ne
val
ence
sta
te.
[Arr
ang
e th
eir
SY
MB
OL
S i
n a
lph
abet
ical
ord
er—
firs
t o
ne
is 1
+ a
nd
th
e o
ther
tw
o a
re 2
+]
Nam
ing
()
ion
s: m
on
ato
mic
an
d p
oly
ato
mic
MO
NA
TO
MIC
--ad
d t
he
suff
ix -
ide
to t
he
stem
of
the
no
nm
etal
’s n
ame.
H
alo
gen
s ar
e ca
lled
th
e h
ali
des
.
PO
LY
AT
OM
IC--
qu
ite
com
mo
n;
oxy
an
ions
are
the
PA
’sco
nta
inin
g o
xy
gen
(Go
, fi
gu
re!)
-hyp
o--
”ate
”th
e le
ast
ox
yg
en
--i
te--
”ate
”1
mo
re o
xy
gen
th
an h
yp
o-
--a
te--
”ate
”1
mo
re o
xy
gen
th
an -
ite
-hyp
er--
-ate
--”a
te”
the
mo
st o
xy
gen
(oft
en t
he
“hy”
is l
eft
off
to r
ead s
imp
ly “
per
”)
Ex
amp
le:
hyp
och
lori
te C
lO
Ch
lori
te
ClO
2
Ch
lora
te C
lO3
Hyp
er o
r m
ore
co
mm
on
ly P
erch
lora
te C
lO4
Yo
u c
an s
ub
stit
ute
an
y h
alo
gen
in
fo
r th
e C
l.
NA
MIN
G I
ON
IC C
OM
PO
UN
DS
: T
he
+ i
on
nam
e is
giv
en f
irst
foll
ow
ed b
y t
he
nam
e o
f th
e n
egat
ive
ion
.
Ato
ms,
Mole
cule
s an
d I
ons
9
Ex
erci
se 3
Na
min
g T
yp
e I
Bin
ary
Co
mp
ou
nd
s
Nam
e ea
ch b
inar
y c
om
po
un
d.
a.
CsF
b.
A1
C1
3c.
L
iH
a.
ces
ium
flu
ori
de
b.
alu
min
um
ch
lori
de
c.
lith
ium
hyd
rid
e
Ex
erci
se 4
Na
min
g T
yp
e II
Bin
ary
Co
mp
ou
nd
s
Giv
e th
e sy
stem
atic
nam
e o
f ea
ch o
f th
e fo
llo
win
g c
om
po
un
ds.
a.
Cu
C1
b.
Hg
Oc.
F
e 2O
3d
. M
nO
2e.
P
bC
12
a.
cop
per
(I)
chlo
rid
e
b.
mer
cury
(II)
oxid
e
c.
iron
(III
) oxid
e
d.
man
gan
ese(
IV)
oxid
e
e.
lead
(II)
ch
lori
de
TY
PE
II:
Involv
e a
tran
siti
on m
etal
that
nee
ds
a
Rom
an n
um
eral
Mer
cury
(I)
is
Hg
2+
2
Ex
cep
tion
s:
thes
e n
ever
need a
Rom
an
nu
mer
al
even
th
ou
gh
tra
nsi
tion
met
als
.
Giv
e u
p a
nd
ME
MO
RIZ
E:
Ag
+,
Cd
2+,
Zn
2+
(“H
eavy
Meta
l B
ad
Gu
ys”
)
Ato
ms,
Mole
cule
s an
d I
ons
10
Ex
erci
se 5
Na
min
g B
ina
ry C
om
po
un
ds
Giv
e th
e sy
stem
atic
nam
e of
each
of
the
foll
ow
ing
co
mp
ou
nd
s.
a.
Co
Br 2
b.
CaC
12
c.
A1
2O
3d
. C
rC1
3
a.
Cob
alt
(II)
bro
mid
e;
b.
Calc
ium
ch
lori
de;
c.
Alu
min
um
oxid
e; d
. C
hro
miu
m(I
II)
chlo
rid
e
Ex
erci
se 6
Na
min
g C
om
po
un
ds
Co
nta
inin
g P
oly
ato
mic
Io
ns
Giv
e th
e sy
stem
atic
nam
e o
f ea
ch o
f th
e fo
llo
win
g c
om
po
un
ds.
a. N
a 2S
O4
b.
KH
2P
O4
c.
Fe(
NO
3) 3
d.
Mn
(OH
) 2e.
N
a 2S
O3
f.
Na 2
CO
3g
. N
aHC
O3
h.
CsC
1O
4
i.
NaO
C1
j.
Na 2
SeO
4k
. K
BrO
3
a.S
od
ium
su
lfa
te;
b. P
ota
ssiu
m d
ihy
dro
gen
ph
osp
ha
te;
c. Ir
on
(III
) n
itra
te;
d. M
an
ga
nes
e(II
) h
yd
rox
ide;
e. S
od
ium
su
lfit
e;f.
S
od
ium
ca
rbo
na
te;
g. S
od
ium
hy
dro
gen
ca
rbo
na
te;
h. C
esiu
m p
erch
lora
te;
i. S
od
ium
hy
po
chlo
rite
;j.
S
od
ium
sel
enit
e;k
. P
ota
ssiu
m b
rom
ate
NA
MIN
G B
INA
RY
CO
VA
LE
NT
CO
MP
OU
ND
S:
(co
val
entl
y b
on
ded
)
Use
pre
fix
es!!
! D
on
’t f
org
et t
he
–id
e en
din
g a
s w
ell.
Ex
erci
se 7
Na
min
g T
yp
e II
I B
ina
ry C
om
po
un
ds
Nam
e ea
ch o
f th
e fo
llo
win
g c
om
po
un
ds.
a.
PC
15
b.
PC
13
c.
SF
6d
. S
O3
e.
SO
2f.
C
O2
a.
Ph
osp
horu
s p
en
tach
lorid
e;
b.
Ph
osp
ho
ru
s tr
ich
lorid
e;
c.
Su
lfu
r h
exafl
uorid
e;
d.
Su
lfu
r t
rio
xid
e;
e.
Su
lfu
r d
ioxid
e;
f. C
arb
on
dio
xid
e
AC
IDS
Nam
ing
aci
ds
is a
ctu
ally
eas
y.
Th
e n
om
encl
atu
re f
oll
ow
s qu
ite
an e
leg
ant
pat
tern
:
Hy
dro
gen
, if
pre
sen
t, i
s li
sted
fir
stfo
llo
wed
by
a s
uff
ix a
nd
fin
ally
th
e w
ord
“ac
id”.
If t
he
neg
ativ
e io
n’s
nam
e en
ds
in:
-id
e
hyd
ro[n
egat
ive
ion
ro
ot]
icac
id
Ex
: h
yd
rosu
lfu
ric
acid
, H
2S
-ate
-i
c ac
idE
x:
sulf
uri
c ac
id,
H2S
O4
-ite
-o
us
acid
Ex
: ch
loro
us
acid
, H
2S
O3
Ato
ms,
Mole
cule
s an
d I
ons
11
PA
INS
IN
TH
E G
LU
TE
US
MA
XIM
US
: th
ese
lov
ely
“cr
itte
rs”
hav
e b
een
aro
un
d l
on
ger
th
an t
he
nam
ing
sy
stem
an
d n
o o
ne
wan
ted
to
ad
apt!
!W
ith
th
e ex
cep
tio
n o
f th
e fi
rst
2 o
n t
his
lis
t, t
he
AP
ex
am
eith
er a
vo
ids
them
alt
og
eth
er o
r g
ives
yo
u t
he
form
ula
. E
x:
ph
osp
hin
e (P
H3—
amm
on
ia’s
co
usi
n),
etc.
-w
ater
-am
mo
nia
-h
yd
razi
ne
-p
ho
sph
ine
-n
itri
c o
xid
e
-n
itro
us
ox
ide
(“la
ug
hin
g g
as”)
Ex
erci
se 8
Na
min
g A
cid
s
Nam
e ea
ch o
f th
e fo
llo
win
g a
cid
s.
a. H
Br
b
. H
BrO
c. H
BrO
2d
. H
BrO
3e.
HB
rO4
f. H
NO
2g
. H
NO
3
a.
hyd
rob
rom
us
aci
d;
b.
hyp
ob
rom
ou
s aci
d;
c. b
rom
ou
s aci
d;
d.
brom
ic a
cid
; e.
per
bro
mic
aci
d;
f. n
itro
us
aci
d;
g.
nit
ric
aci
d
Ato
ms,
Mole
cule
s an
d I
ons
12
Ex
erci
se 9
Na
min
g V
ari
ou
s T
yp
es o
f C
om
po
un
ds
Giv
e th
e sy
stem
atic
nam
e fo
r ea
ch o
f th
e fo
llo
win
g c
om
po
un
ds.
a.
P4O
10
b.
Nb
2O
5c.
L
i 2O
2d
. T
i(N
O3) 4
a.T
etra
ph
osp
horu
s d
ecoxid
e;b
. N
iob
ium
(V)
oxid
e;
c.
Lit
hiu
m p
eroxid
e;
d.
Tit
an
ium
(IV
) n
itra
te
Ex
erci
se 1
0W
riti
ng
Co
mp
ou
nd
Fo
rmu
las
fro
m N
am
es
Giv
en t
he
foll
ow
ing
sy
stem
atic
nam
es,
wri
te t
he
form
ula
fo
r ea
ch c
om
po
un
d.
a.
Van
adiu
m(V
) fl
uo
rid
eb
. D
iox
yg
en d
iflu
ori
de
c.
Rub
idiu
m p
ero
xid
ed
. G
alli
um
ox
ide
a.
VF
5;
b.
O2F
2;
c.
Rb
2O
2d
. G
a2O
3
For
the
vis
ual
lea
rner
s am
ong y
ou,
her
e’s
a “C
hea
t S
hee
t”.
Pra
ctic
e, p
ract
ice,
pra
ctic
e!
Ato
ms,
Mole
cule
s an
d I
ons
13
Chemical Nomenclature
Chemical Nomenclature Naming and Writing Chemical Formulas
VOCABULARY Ion — an atom or group of atoms that has gained or lost electrons Monatomic ion — an atom that has gained or lost electrons and has a charge Polyatomic ion — a group of covalently bound atoms that has a charge Anion — a negatively charged ion Cation — a positively charged ion Charge — the positive or negative value assigned to an ion as a result of having lost or gained electrons Oxidation number — hypothetical charge a covalently bound atom would have IF its bonds were ionic Acid — a compound that donates a H+ ion during a reaction Ionic compound — a compound made of positively and negatively charged ions Molecular compound — a compound held together by shared pairs of electrons Hydrocarbon — a compound composed of carbon and hydrogen Alcohol — a hydrocarbon that has had one or more of its hydrogens replaced with –OH groups
INTRODUCTION Writing chemical formulas will open your eyes to the chemical world. Once you are able to write correct chemical formulas there are four naming systems you will need to master. The trick lies in recognizing which naming system to use! Use the following guidelines when making your decisions about how to name compounds. If the chemical formula for the compound starts with H, it is an acid. Use the Naming Acids
rules. If the chemical formula for the compound starts with C and contains quite a few H’s and
perhaps some O’s, it is organic. Use the Naming Organic Compounds rules. If the chemical formula for the compound starts with a metal it is most likely ionic. Use the
Naming Binary Ionic Compounds rules. If the chemical formula for the compound starts with a nonmetal other than H or C, use the
Naming Binary Molecular Compounds rules. It is essential that you memorize at least 9 common polyatomic ions. Polyatomic ions are groups of atoms that behave as a unit and possess an overall charge. If more than one copy of a polyatomic ion is needed to create a chemical formula, the ion must be enclosed in parentheses before adding the subscripts. You need to know their names, formulas and charges. If you learn the nine that follow, you can determine the formula and charges for many others from applying two simple patterns.
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Chemical Nomenclature
Name of Polyatomic Ion: Formula & Charge: Ammonium ion NH4
+
Acetate ion C2H3O2
− Cyanide ion CN−
Hydroxide ion OH− Nitrate ion NO3
− Chlorate ion ClO3
−
Sulfate ion SO4
2− Carbonate ion CO3
2−
Phosphate ion PO43−
Pattern 1: The -ates “ate” one more oxygen than the -ites however, their charge does not change as a result. For instance, if you know nitrate is NO3
−, then nitrite must be NO2−. If you know
phosphate is PO43−, then phosphite must be PO3
3−. You can also use the prefixes hypo- and per- with the chlorate series. Perchlorate, ClO4
−, was really “hyper and -ate yet another oxygen” when compared to chlorate, ClO3
−. Hypochlorite is a double whammy. It is -ite and therefore “ate” one less oxygen than chlorate and it is hypo- which means “below” so it “ate” even one less oxygen than plain chlorite so its formula must be ClO−. You can substitute the other halogens for chlorine and make similar sets of this series. Pattern 2: The -ates with charges less than negative one, meaning ions with charges of −2, −3, etc., can have an H added to them to form new polyatomic ions. For each H added the charge is increased by a +1. For instance, CO3
2− can have an H added and become HCO3−. HCO3
− is called either the bicarbonate ion or the hydrogen carbonate ion. Since phosphate is negative three, you can add one or two hydrogens to make new polyatomic ions, HPO4
2− and H2PO4−. The names are
hydrogen phosphate and dihydrogen phosphate, respectively. If you continue adding hydrogen ions until you reach neutral, you’ve made an acid! That means you need to see the Naming Acids rules.
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Chemical Nomenclature
Pattern 3: Use of the following periodic table will also come in handy. Notice the simple patterns for determining the most common oxidation states of the elements based on their family’s position on the periodic table. Notice the IA family is +1 while the IIA family is +2. Skip across to the IIIA family, and notice that aluminum is +3. Working backwards from the halogens, or VIIA family, they are most commonly −1 while the VIA family is −2 and the VA family is −3. The IV A family is “wishy-washy,” and can be several oxidation states, the most common being 4.
NAMING ACIDS How do I know it is an acid? The compound’s formula begins with a hydrogen, H, and water doesn’t count. Naming acids is extremely easy, if you know your polyatomic ions. There are three rules to follow: H + element: If the acid has only one element following the H, then use the prefix hydro-
followed by the element’s root name and an -ic ending. HCl is hydrochloric acid. H2S is hydrosulfuric acid. When you see an acid name beginning with “hydro”, think “Caution, element approaching!” (HCN is an exception since it is a polyatomic ion without oxygen, and it is named hydrocyanic acid.)
H + -ate polyatomic ion: If the acid has an “-ate” polyatomic ion after the H, then it makes an “-ic” acid. H2SO4 is sulfuric acid.
H + -ite polyatomic ion: If the acid has an “-ite” polyatomic ion after the H, then it makes an “-ous” acid. H2SO3 is sulfurous acid.
When writing formulas for acids you must have enough H+ added to the anion to make the compound neutral. Also note that -ate and -ite polyatomic ions contain oxygen so, their acids are often referred to as oxyacids.
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Chemical Nomenclature
NAMING ORGANIC COMPOUNDS How do I know it is organic? The chemical formula will start with a C followed by hydrogens and may even contain some oxygen. Most of the organic carbons you will encounter will be either hydrocarbons or alcohols. These are the simplest of all to name. Memorize the list of prefixes in Table B found in the conclusion questions. The prefixes correspond to the number of carbons present in the compound and will be the stem for each organic compound. Notice that the prefixes are standard geometric prefixes once you pass the first four carbons. This silly statement will help you remember the order of the first four prefixes: “Me Eat Peanut Butter.” This corresponds to meth-, eth-, prop-, and but- which correspond to 1, 2, 3, and 4 carbons, respectively. Now that we have a stem, we need an ending. There are three common hydrocarbon endings that you will need to know as well as the ending for alcohols. The ending changes depending on the structure of the molecule. -ane - alkane (all single bonds & saturated) CnH2n+2; The alkanes are referred to as saturated
hydrocarbons because they contain only single bonds and thus, the maximum number of hydrogen atoms.
-ene = alkene (contains one double bond & unsaturated) CnH2n; The alkenes are referred to as unsaturated hydrocarbons because a pair of hydrogens have been removed to create the double bond.
-yne ≡ alkyne (contains one triple bond & unsaturated) CnH2n−2; The alkynes are also referred to as unsaturated, because two pairs of hydrogens have been removed to create the triple bond. The term polyunsaturated means that the compound contains more than one double or triple bond.
-ol – alcohol (one H is replaced with a hydroxyl group, -OH group, to form an alcohol) CnH2n+1OH; Do not be fooled—this looks like a hydroxide ion, but is not! It does not make this hydrocarbon an alkaline or basic compound. Do not name these as a hydroxide! C2H6 is ethane while C2H5OH is ethanol.
NAMING BINARY IONIC COMPOUNDS How do I know it is ionic? The chemical formula will begin with a metal cation (+ ion) or the ammonium cation. The ending is often a polyatomic anion. If only two elements are present, they are usually from opposite sides of the periodic table, like KCl. If the metal can have more than one oxidation state, be prepared to use a Roman numeral indicating which oxidation state the metal is exhibiting. Group IA alkali metals, Group IIA alkaline earth metals, aluminum (Al), silver (Ag), cadmium (Cd) and zinc (Zn) are exceptions to the Roman numeral rule because their charges are constant. Group IA metals are always +1, Group IIA metals are always +2, Al is always +3, Ag is always +1, and Cd and Zn are always +2 in chemical compounds. In order to name these compounds, first name the ions.
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Chemical Nomenclature
Naming positive ions: Metals commonly form cations. Monatomic positive ions in Group A are named by simply writing the name of the metal from
which it is derived. Al3+ is the aluminum ion. Metals often form more than one type of positive ion so Roman numerals (in parentheses)
follow the ion’s name. Cu2+ is the copper(II) ion. Remember the exceptions — IA, IIA, Al, Ag, Cd, Zn.
NH4+ is the ammonium ion. It is the only positive polyatomic ion that you will encounter.
Naming negative ions: Nonmetals commonly form anions (− ions). Most of the polyatomic ions are also negatively-charged. Monatomic negative ions are named by adding the suffix -ide to the stem of the nonmetal’s
name. Group VIIA, the Halogens are called the halides. Cl− is the chloride ion. Polyatomic anions are given the names of the polyatomic ion. You must memorize these as
instructed. NO2− is the nitrite ion.
Naming the Compound: The + ion (cation) name is given first followed by the name of the negative ion (anion). Remember, to include the Roman numeral that indicates a metal’s charge for the many metals that have more than one oxidation state. No prefixes are used in naming ionic compounds.
NAMING BINARY MOLECULAR COMPOUNDS How will I know it is a molecular compound? The chemical formula will contain a combination of nonmetals, both lying near each other on the periodic table. No polyatomic ions will be present. Use the following set of prefixes when naming molecular compounds.
Subscript Prefix 1 Mono-
[usually used only on the second element; such as carbon monoxide or nitrogen monoxide]
2 di- 3 tri- 4 tetra- 5 penta- 6 hexa- 7 hepta- 8 octa- 9 nona- 10 deca-
Naming the Compound: The name of the element with the positive oxidation state is given first, followed by the name of the element with the negative oxidation state. Use prefixes to indicate the number of atoms of each element. Don’t forget the -ide ending. If the second element’s name begins with a vowel, then the “a” at the end of the prefix is usually dropped. N2O5 is dinitrogen pentoxide not dinitrogen pentaoxide. PCl5 is phosphorous pentachloride not phosphorous pentchloride.
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Chemical Nomenclature
FORMULA WRITING Naming is the trickiest part! Once you have been given the name, the formula writing is easy as long as you have memorized the formulas and charges of the polyatomic ions. The prefixes of a molecular compound make it really easy to write the formula since the prefix tells you how many atoms are present for each element. Roman numerals are your friend; they tell you the charge of the metal ions that can have more than one oxidation state and thus form positive ions with different charges. Remember that Group IA, Group IIA, Al, Ag, Cd, & Zn are usually not written with a Roman numeral; you must know their charges. The most important thing to remember is that, the sum of the charges must add up to zero in order to form a neutral compound. The crisscross method is very useful—the charge on one ion becomes the subscript on the other. If you use this method, you must always check to see that the subscripts are in their lowest whole number ratio! Here are some examples: potassium oxide K1+ O2− K1 O2 K2O
iron(III) chlorate Fe3+ ClO31− Fe3 ClO3
1 Fe(ClO3)3
tin(IV) sulfite Sn4+ SO3
2− Sn4 SO32 Sn2(SO3)4 Sn(SO3)2
zinc acetate Zn2+ C2H3O2
1− Zn 2 C2H3O21 Zn(C2H3O2)2
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Chemical Nomenclature
PURPOSE To master the skill of writing and naming chemical formulas.
MATERIALS
Each lab group will need the following: bag, zipper-lock, quart copy of student formula manipulatives scissors
PROCEDURE
1. Carefully cut out the models on Template 1. Group them by similar charge or oxidation state.
2. Trace over the symbol and oxidation state of each element using colored markers and apply the color scheme below:
3. Notice how the models fit together. If an element has a +3 oxidation state, it requires three elements with a −1 oxidation state to create a complete compound and the subscripts would reflect a 1:3 ratio.
4. Review the rules for naming acids and complete Table A on your student answer page. Use the models you created from Template 1 as needed. Supply either the acid’s name or its formula to complete Table A.
5. Review the rules for naming binary ionic and molecular compounds. Use the models you created from Template 1 as needed. Supply the compound’s formula and name to complete Table C. If the charge or oxidation state is missing from the table, it is because you should already know them or be able to determine them due to their position in the periodic table.
6. Carefully cut out the shapes on Template 2. Each carbon model has 4 inward notches. The model “bonds” found on Template 2 are for connecting the carbons. These shapes will be used to help you with organic compounds. There is no need to color them.
7. Review the rules for naming organic hydrocarbons and alcohols. Use your models from Template 2 as needed. Fill in the missing formulas and names for each compound in Table B.
Safety Alert Use care when handling scissors.
Color Oxidation StateBlue +1 Red −1
Yellow +2 Green −2 Purple +3 Pink −3
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Chemical Nomenclature
Chemical Nomenclature Naming and Writing Chemical Formulas
All You Really Need to Know About Chemical Names and Formulas SUMMARIZED In this flowchart, D and J in the general formula DxJy can represent atoms, monatomic ions, or polyatomic ions.
D = Group IA, IIA, _Al, Cd, Ag, or Zn?
D = Group IA, IIA, _ Al, Cd, Ag, or Zn?
DxJy
Yes
No
Compound is an acid;use the table below
Compound MUSTcontain a polyatomicicon its name ends in-ite or -ate
Name the ions; usea Roman numeral toindicate the chargeon the cation
Name the ions
Compound is binarymolecular; useprefixes in the name
Name the ions; usea Roman numeral toindicate the charge on the cation
Name the ions
Compound isbinary its name
ends in -ide
No
NoYes
No Yes
Yes
No
Yes
D = metal
More thanTWO elements?
D = H
NamingAcids
Anion ending Example Acid name Example
hydrosulfuric acid
sulfurousacid
sulfuric acid
(stem)-icacid
(stem)-ousacid
Hydro-(stem)-icacid
–ate
–ite
–ide
SO32-
sulfite
S2-
sulfide
SO42-
sulfate
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Chemical Nomenclature
CONCLUSION QUESTIONS
Table A
Acid Formula Acid Name
HCl
hypochlorous acid
chlorous acid
chloric acid
perchloric acid (“hyperchloric” acid)
HNO3
hydrobromic acid
H3PO4
H3PO3
hydrocyanic acid
HC2H3O2
carbonic acid
hydroiodic acid
HF
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Chemical Nomenclature
Table B
# of carbon atoms = n prefix or stem -ane
CnH2n+2
-ene
CnH2n
-yne
CnH2n−2
-anol
CnH2n+1OH
1 meth-
None here because you must have at least 2 carbons for multiple
bonding
CH3OH
methanol
2 eth-
3 prop- C3H6
propene
4 but-
5 pent- C5H12
pentane
6 hex-
7 hept- C7H15OH
heptanol
8 oct- C8H14
octyne
9 non-
10 dec-
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Chemical Nomenclature
Table C
Ag+ Pb2+ Cu+ Ba2+ NH4+ Al3+ Mn2+
N3−
O2−
Br−
S2−
SO42−
ClO2−
PO33−
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Chemical Nomenclature
Al3+
NH4+
Mn2+
H+
H+H+
H+
H+H+
Ag+Cl-
NO3-
Br-
Pb2+
Cu+
Ba2+
N3-
O2-
S2-
SO42-
H+
H+
H+
H+H+
Template 1
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Chemical Nomenclature
ClO-
C2H3O2-
PO33-
S2-
CO32-
ClO2-
ClO3-
ClO4-
F-
I-
CN-
PO43-
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Chemical Nomenclature
Template 2
CCC C
C
C
C
C
C
C
CC HHH
HH
HH
H
HHH
H
H
HH
HH
HH
H
HHH
H
OH
OH
OH
Use the models below as single, double and triple
bonds for connecting carbons.
Remember, DO NOT allow C to have more
than FOUR total bonds!
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