Essential Question: How can one explain the structure, properties, and interactions of matter?
Chemistry
AP Chem. Enduring Understanding 3A
Chemical changes are represented by a
balanced chemical reaction that identifies
the ratios with which reactants react and
products form.
Chm.2.2.4 Analyze the
stoichiometric relationships inherent
in a chemical reaction.
4DM7a* 4DM7b4DM12**4DM13**
Chm.2.2.3 Analyze the Law of
Conservation of Matter and how it
applies to various types of chemical
equations (synthesis, decomposition,
single replacement, double
replacement, and combustion).
4DM13**4DM12**4DM7a*4DM7b
Chm.2.2.2 Analyze the evidence of
chemical change. 4D/M11
Matter: Structure, Properties and Change
Grades 9 – 12
In what ways do the building blocks (atoms) combine to create all of the substances and structures in the
universe? There is a hierarchy of structure within matter. Atoms may interact to form individual molecules or
arrange in extended patterns with no defined endpoint. Atoms and molecules combine to form larger, more
complex structures, natural or manufactured, with an extensive range of properties. (link to ET1.A) Structures
made of atoms and molecules exist over a huge range of scales—from diatomic molecules in a gas to stars.
Substances can exist in different states: solid, liquid, gas or plasma depending on the temperature and pressure.
However, many substances are not easily classified into these categories (e.g., gels, colloids). In a plasma state, a
substance is gaseous but a large proportion of the particles are ionized, which affords very different properties
than a neutral gas. (e.g., conducts electricity). Atoms themselves have substructure. Each atom has a charged
substructure consisting of a nucleus, which is made of protons and neutrons, surrounded by electrons. The
patterns of the periodic table can be related to the patterns of the outermost electrons in the atom, which are those
that are involved in chemical bonding. (A few basic types of interactions, or bonds: metal•non-metal (ionic); nonmetal•non-metal (covalent); metal•metal (metallic)). Models of electrical attractions and repulsions involving
electrons and atomic nuclei help explain the structure and many properties of substances. (link to PS2.A) The
periodic table orders elements horizontally by the number of protons in the atom’s nucleus and places those with
similar chemical properties in columns. The repeating patterns of this table reflect patterns of outer electron states.
The structure and interactions of matter at the bulk scale are determined by electrical forces within and between
atoms. Stable forms of matter are those in which the electric
and magnetic field energy is minimized. A stable molecule has less energy, by an amount known as the binding
energy, than the same set of atoms separated; one must provide at least this energy in order to take the molecule
apart. PS1A pg 109
What is the source of the properties of a substance? Using a broader range of properties to characterize
substances not only aids in distinguishing between substances, but also provides more information for
determining useful applications for them. The properties for different bulk quantities of a substance are the same.
However, as the size of a sample transitions between the bulk material and individual atoms or molecules the
intrinsic properties become less reliable, so new, often unexpected, properties that can lead to new functionality
are observed. The four classes of the elements (metals, nonmetals, semimetals, and the noble gases) are defined
based on how they interact with other elements, which is related to their electronic structure. (link to PS1.A) The
properties of different substances result from the configurations of atoms in them (e.g. varied types of molecules,
crystalline or metallic extended structures) Chemical properties of elements depend on the atomic substructure,
particularly the outermost electron layer. PS 1B pg111 (link toPS1.A)
What causes transformations to occur and how can we predict the outcome and rates of transformations?
Systems change in predictable ways, understanding what drives the transformations and the cycles within a
system help us predict its behavior in a variety of conditions. Collision theory provides a qualitative model for
explaining the condition-dependence of rates of chemical and nuclear processes.
Even processes that release energy can require some collision energy in order to occur because if the reactants or
nuclei collide at low relative speed they bounce apart before they get close enough to initiate the reaction. Matter
is stable because interactions within the matter reduce its energy compared to the energy of any pieces it might
otherwise fall apart into. It requires addition of energy to take it apart in any way (e.g., to pull off a sticky tape).
The term binding energy is used to describe the size of the energy reduction between the separated parts and the
stable whole (i.e., the energy needed to take the system apart). Many of the processes in our daily lives involve
chemical transformations in which atoms in a set of colliding molecules get rearranged into a different set of
outgoing molecules but the number of atoms of each type is not changed. At the sub-atomic level chemical
processes involve changes in the distribution and motion of electrons, and thus in chemical binding energies.
Changes in binding energy are balanced by differences in the kinetic energy of the molecules before and after the
collision. Nuclear processes include fusion and radioactive decays of unstable nuclei (fission, beta and gamma
radiation). Nuclear processes involve changes in nuclear binding energies and masses, and release more energy
per atom involved than do chemical processes. In these processes atoms change type but the total number of
protons plus neutrons does not change. Total electric charge does not change in any process, but positive and
negative charges can be separated starting from charge-neutral
material.PS1C pg 113
Essential Question: How can one explain the structure, properties, and interactions of matter?
6-8
To Chem
8.P.1.4 Explain how the idea of atoms
and a balanced chemical equation
support the law of conservation of
mass. 4D/M13, M7b
8.P.1.3 Compare physical changes such as
8.P.1.1 Classify matter as elements, compounds,
or mixtures based on how the elements are
packed together in arrangements. 4D/M1cd
size, shape and state to chemical changes
that are the result of a chemical reaction to
include changes in temperature, color,
formation of a gas or precipitate.
8.P.1.2 Explain how the physical properties of
elements and their reactivity have been used
to produce the current model of the Periodic
Table of elements. 4D/M6a
6.P.2.2 Explain the effect of heat on the
motion of atoms and molecules through a
description of what happens to particles
during a change in phase. 4D/M3ab
6.P.2.1 Recognize that all matter is made up
of atoms (4D/M1a) and atoms of the same
element are all alike, but are different from
the atoms of other elements. 4D/M1b
6.P.2.3 Compare the physical properties of
pure substances that are independent of the
amount of matter present including density,
boiling point, melting point and solubility to
properties that are dependent on the amount of
matter present to include volume, mass and
weight. 4D/M10
Matter: Structure, Properties and Change
Grades 6 – 8
How do the building blocks of matter help explain the diversity of materials that exist in the
world?(sub-microscopic (Link to PS1.B)Substances can exist in different states: solid, liquid and gas,
depending on the temperature and pressure. Regardless of the state, all matter has mass, and the mass
does not change when matter goes from one state to another. Models of matter consisting of extremely
tiny particles that are constantly in motion, with interactions between the particles, can explain states of
matter and changes of matter with temperature (in these models particles are non-specific).The particles
that make up matter are so small that they cannot be observed through a light microscope, but can be
detected and manipulated by modern tools. Despite the immense variation and number of substances, all
are made from a limited number of types of atoms, called elements. All substances are made from some
100 different types of atoms, which combine with one another in various ways. Atoms form molecules
that range in size from two to thousands of atoms. Pure substances are made from a single type of atom or
molecule; each pure substance has characteristic physical and chemical properties (for any bulk quantity
under given conditions) that can be used to identify it. Gases and liquids are made of molecules or inert
atoms that are moving about relative to each other. In a liquid, the molecules are constantly in contact
with each other; in a gas, they are widely spaced except when they happen to collide. In a solid, atoms are
closely spaced and vibrate in position but do not change relative locations. Solids may be formed from
molecules, or they may be extended structures with repeating subunits (e.g., crystals). The changes of state
that occur with variations in temperature or pressure can be described and predicted using these
models of matter. (Boundary: Predictions here are qualitative, not quantitative.) Each type of atom
has distinct mass and chemical properties. The Periodic Table organizes the elements by their mass and
chemical properties and provides a useful reference for predicting how they will combine. Molecules form
due to interactions between atoms; molecules range in size from two to hundreds of atoms. Atoms may
interact to form distinct molecules or arrange in extended patterns with no defined endpoint (e.g. crystals,
metals). The chemical composition, the arrangement of atoms, and the way they interact and move
determines the state and properties of a substance. The thermal motion of the atoms increases with
temperature. PS1A pg 108
How can we reliably distinguish between substances? Each pure substance has characteristic physical
properties (density, boiling and melting points, and solubility are appropriate at this level) and unique
chemical properties, which are relatively insensitive to the amount of the sample, so are useful for
distinguishing one substance from another. Measuring the intrinsic properties helps identify and
distinguish between different substances. Measuring more precisely, or more different properties,
increases confidence of conclusions. Elements can be grouped as highly reactive metals, less-reactive
metals, highly reactive nonmetals and some elements that are non-reactive gases. Many substances react
chemically in characteristic ways with other substances to form new substances with different intrinsic
properties. This change in properties results from changes in the way atoms from the original substances
combine and arrange. PS1B pg 111
What happens to the building blocks when transformations occur (sub-microscopic)? At this level,
only non-nuclear transformations are considered. When substances undergo transformations (except
nuclear), the atoms and molecules that make up the substance may be arranged differently. However, the
total number and identity of atoms remains the same. All transformations involve exchange of energy. The
total amount of energy stays the same before, during and after any transformation. There is a relationship
between temperature and kinetic energy of thermal motion. Applying this idea to a particulate model of
matter helps explain why temperature changes affect the structure and properties of matter. Observed
patterns of change in a system allow predictions about the future of the system. Under constant conditions,
a system starting out in an unstable state will continue to change until it reaches a stable condition
(e.g. hot and cold objects in contact). Although a system may appear to be unchanging, changes occurring
at the molecular level in opposite directions may occur at equal rates.
Essential Question: How can one explain the structure, properties, and interactions of matter?
3-5
To 6.P.2.1
5.P.2.3 Summarize properties of original
materials, and the new material(s)
formed, to demonstrate that a change has
occurred. 4D/E4
To 6.P.2.1
3.P.2.3 Supporting Objective
Many kinds of changes occur
faster under hotter conditions.
See Content Description.
3.P.2.3 Summarize changes that occur
to the observable properties of
materials when different degrees of
heat are applied to them, such as
melting ice or ice cream, boiling water
or an egg, or freezing water. (4D/E1)
3.P.2.2 Compare solids, liquids, and
gases based on their basic properties.
4B/E3
Grades 3 – 5
To 8.P.1.4
5.P.2.2 Compare the weight of an object
to the sum of the weight of its parts
before and after an interaction. 4D/E2
5.P.2.1 Explain how the sun’s energy
impacts the processes of the water cycle
(including evaporation, transpiration,
condensation, precipitation). 4B/E3
To 6.P.2.3
4.P.2.3 Classify rocks as metamorphic
or sedimentary based on their
composition, how they are formed and
the processes that create them. 4C/E2
4.P.2.2 Explain how minerals are identified
using tests for the physical properties of
hardness, color, luster, cleavage and
streak. 4G/E3
Matter: Structure, Properties and Change
How do the parts of an object affect its structure and function? (macroscopic)All substances are
considered matter. Matter can exist as solid, liquid, or gas. In all forms it can be felt and weighed.
Matter of any type can be subdivided into particles that are too small to see, but even then the
matter still exists and can be detected by other means (e.g., by weighing or by its effects on other
objects). For example, a model showing that gases are made from matter particles that are too
small to see and are moving freely around in space can explain many observations, including the
inflation and shape of a balloon; the effects of air on larger particles or objects (e.g., leaves in
wind, dust suspended in air); and the appearance of visible scale water droplets in condensation,
fog, and, by extension, also in clouds or the contrails of a jet. You can make a great variety of
objects with just a few types of components. The structure, properties and uses of the objects depend
on the nature of the components and they ways they attach to one-another, but can be quite different
from those of the components. Knowing about the characteristics of materials helps design uses of
them. Many substances can exist as solid, liquid or gas depending on the temperature. Solids have
definite shape and volume, liquids also occupy definite volume, but not shape, gases are made of
particles too small to see that move around throughout the full volume of any container. The amount
(weight) of matter is conserved when it changes form, even in transitions in which it seems to
vanish (e.g., sugar in solution, evaporation in a closed container). Measurements of a variety of
properties (e.g., hardness, reflectivity) can be used to identify particular materials. (Boundary: At
this grade level, mass and weight are not distinguished, and no attempt is made to define the
unseen particles or explain the atomic-scale mechanism of evaporation and condensation.)PS1A
pg 108
What characteristics are useful for describing and classifying substances? Materials can be
described and classified by their physical properties such as hardness, flexibility, durability, resistance
to water and fire, and ease of conducting heat. Solids can also be classified as metals and non-metals
(density is not to be introduced at this level). Measurements of specific properties provide better ways
of telling one substance from another than relying only on what it looks or feels like. When two or
more different substances are mixed, a new substance with different properties may be formed; such
occurrences depend on the substances and the temperature. No matter what reaction or change in
properties occurs, the total weight of the substances does not change. You cannot make matter but you
can refine and process naturally occurring substances to make a great variety of new types of materials
with specific useful properties. (Boundary: Mass and weight are not distinguished at this grade level.)
PS1 B pg 110
To flow of matter
in Ecosystems
3.P.2.1 Recognize that air is a substance
that surrounds us, takes up space and
has mass. 4B/E4
4.P.2.1 Compare the physical properties
of samples of matter: (strength,
hardness, flexibility, ability to conduct
heat, ability to conduct electricity, ability
to be attracted by magnets, reactions to
water and fire). 4D/E6
What happens to the parts of a system when the system changes? (macroscale) When two or more
different substances are mixed, often a new substance with quite different characteristics can be
formed, especially if the mixture is heated. Materials seem to appear or disappear in some
transformations (e.g., dissolving, evaporation, burning). In the invisible state, the materials still exist
but in pieces too small to see. You can detect their presence in various ways. No matter how the parts
are put together to make a product, the weights of the individual parts add up to the weight of the
product. Changing temperature can cause some materials to evaporate or condense. Conditions and
properties of the objects within a system affect how fast or slowly a process occurs (examples include
diffusion, rates of reactions). Collisions between objects change their motion. Sometimes the collision
also causes a change in the object. A system can appear to be unchanging when flows or processes we
cannot see are going on in opposite but equal rates. Systems can change in many patterns over time. A
process may move in one direction, shift back and forth, or repeat in cyclical pattern (e.g., day and
night or weight on a spring).
Essential Question: How can one explain the structure, properties, and interactions of matter?
Matter: Structure, Properties and Change
K-2
To 5.P.2.2
Grades K – 2
2.P.2.1 Supporting Objective:
Students know things can be done
to materials to change some of
their properties, but not all
materials respond the same way to
what is done to them. 4D/P2
See Content Description
`
To 5.P.2.1
What kind of parts are objects made of? (macroscopic)
Objects are generally made of different parts. The parts can be made of
different materials. Materials can be natural or manufactured from natural
resources. The identity, characteristics and function of an object depend
on the materials/building blocks used to make it, and the way they fit
together. The same materials can exist as a solid or a liquid depending
on the temperature. Solids have a definite shape while liquids flow to the
lowest level in the container. Different kinds of matter exist (e.g., wood,
metal, water), and many of them can be either solid or liquid, depending on
temperature. Matter can be described and classified by its observable
properties (e.g., visual, aural, textural), by its uses, and by whether it occurs
naturally or is manufactured. Different properties are suited to different
purposes. A great variety of objects can be built up from a small set of pieces
(e.g., blocks, construction sets). Objects or samples of a substance can be
weighed, and their size can be described and measured. (Boundary: volume
is introduced only for liquid measure.)PS1A pg 108
How can we describe and sort objects?
Objects can be described and sorted based on visual and tactile properties
of the materials from which they are made. When objects are taken apart,
their separate parts generally don’t have the characteristics of the object.
Materials with different properties can be matched to different uses. Heating
2.P.2.2 Compare the amount
(volume and mass) of water in a
container before and after
freezing. 4B/P2
2.P.2.3 Compare what happens to
water left in an open container over
time as to water left in a closed
container. 4B/P3
2.P.2.1 Give examples of matter that
changes from a solid to a liquid and
from a liquid to a solid by heating
and cooling. 4B/P2
K.P.2.2 Classify objects by observable
properties (including size, color shape,
texture weight and flexibility).
or cooling a substance may cause changes that can be observed. Sometimes these
changes are reversible (e.g., melting and freezing), and sometimes they are not (e.g.,
baking a cake, burning fuel). PS1 B pg 110
To 5.P.2.3
In what way do things around us change? (macroscopic)
Some changes happen quickly. Some changes happen slowly. Changes
that happen very fast or very slowly are sometimes hard to see. Changing
temperature can cause a substance to change form but it can still remain
the same substance (e.g., melting and refreezing).
K.P.2.1 Compare the observable properties of different kinds of
materials (clay, wood, cloth, paper, etc.) from which objects are made
and how they are used. 4D/P1
SM CR
Changes of State
Changing vs.
Constant Properties
Conservation of Matter
Basic Ingredients:
Atoms and Molecules
Chemical Reactions