Modeling Chemistry Course Outline
Matter is composed of featureless spheres (BB’s) which have mass
Unit 1
Simple Particle and volume. These particles are essentially the “atoms” proposed
Describing by Democritus.
Matter
Mass is a measure of how much stuff the object is made of.
Matter is conserved during all kinds of change because we are just
rearranging the spheres.
Volume is a measure of how much space the object occupies.
These are properties of an object.
Density describes how much stuff for each unit volume.
This is a property of a substance.
Our BB’s are in constant, random, thermal motion, the speed of
Unit 2
Simple Particle which depends on the temperature. The BB's interact with one
Energy and another by collisions.
States, part 1
Matter can exist in three phases, which are characterized by the
arrangement of particles. This arrangement affects the density and
compressibility of each phase.
Particles of matter are in constant motion.
Thermal energy (Eth) is related to the motion of the particles and is
measured by temperature.
Energy is transferred from particle to particle via collisions.
Pressure of gases is explained in terms of the collisions of the
particles with the sides of the container. There are functional
relationships between the pressure of a gas and the volume,
temperature and the number of gas particles in a container.
Unit 3
Sticky
Particle:
Energy and
States, part 2
Our BB's also exert attractions on one another. Energy is a
conserved substance-like quantity that is stored in various accounts
and transferred in various ways.
Matter can exist in three phases - these are characterized by the
arrangement of the particles and the attractive forces that bind
them. We call these particles “molecules” from the Latin (little
lumps of stuff).__ Energy is involved whenever the state (phase,
temperature, etc) of the system changes.__ Attractions between
particles lower the energy of the system; the more tightly bound the
particles, the lower the energy due to interactions – we call this
account: phase energy. During phase changes, changes in phase
energy
(Eph ) result in a new arrangement or orientation of the particles._
Energy can be transferred between the system and surroundings via
heating (collisions of countless microscopic particles), working
(due to forces between macroscopic bodies or due to the expansion
or contraction of gases) and radiating (due to the emission or
absorption of photons).
Unit 4
Bonded
Particles:
Describing
Substances
The particles that make up substances can be compounded from
smaller particles. The fact that compounds have definite
composition leads us to Dalton’s model of the atom. Evidence from
combining volumes and definite mass composition allows us to
deduce formulas of compounds.
Matter is composed or pure substances or mixtures of these pure
substances. The molecules of pure substances have definite
composition and properties whereas the composition and properties
of mixtures are variable. Molecules of pure substances can be
broken down into simpler particles (atoms or molecules).
Unit 5
Counting
Bonded
Particles:
The Mole
From Avogadro's Hypothesis we are able to count molecules by
weighing macroscopic samples.
Because equal volumes of gases, at the same T and P, have equal
numbers of molecules, we can determine the relative mass of
individual molecules be weighing larger samples of them. From
these results it is possible to determine the molar masses of the
elements. Using these masses and formulas of compounds, one can
determine molar masses of compounds. These tools allow one to
relate “how much stuff” to “how many particles”.
Unit 6 materials We find that atoms have the property of charge and some internal
structure; we use the Thomson model of the atom to account for
our observations.
Two kinds of charge exist in atoms. Charge plays a role in the
attractive forces that hold solids and liquids together and binds the
atoms in molecules or crystal lattices. Molecular substances are
composed of neutral molecules, whereas ionic substances are
lattice-work arrangements of ions. These two kinds of substance
have different structures and physical properties.
Unit 7
materials
Chemical reactions involve the rearrangement of atoms in
molecules to form new molecules. This rearrangement of atoms
results in a change in the chemical potential energy (Ech ) of the
system. This invariably produces changes in thermal energy (Eth ),
and results in energy transfers between system and surroundings.
Mass is conserved because the atoms in the products are the same
as those found in the reactants. This is represented symbolically as
a balanced chemical equation. Because the grouping of atoms into
molecules is changed in a chemical reaction, the total number of
molecules (or formula units) in the products need not be the same
as that in the reactants.
Substances store varying amounts of chemical potential energy (Ech
) due to the arrangement of atoms. It is not possible to measure this
amount of energy directly. However, rearrangement of atoms
during reaction produces changes in Eth; the resulting energy
transfers (as Q) between system and surroundings can be measured.
From these one can deduce differences in the Ech of reactants and
products. Energy bar graphs are a useful tool for accounting for
energy (stored and transferred) during chemical change.
Unit 8
Relating
"How
Much"to
"How Many"
Bonded
Particles
Stoichiometry
I
Equations representing chemical reactions relate numbers of
particles (molecules or formula units) to weighable amounts of
these particles.
Unit 9
Relating
"How
Much"to
"How Many"
Bonded
Particles
Stoichiometry
II
Equations representing chemical reactions can also relate numbers
of particles (molecules or formula units) to volumes of gases,
solutions and to the change in chemical potential energy.
Stoichiometry should not be reduced to a formulaic approach
designed to “get the right answer”. The fact that proportional
relationships exist between the numbers of particles involved in a
chemical reaction allows us to make predictions about “how much
stuff” will be required or produced. The reasoning of stoichiometry
is best understood in the context of the whole reaction process,
which is organized in the BCA table. This table stresses the
proportional relationships that exist between moles of reactants and
products, discouraging a formulaic approach designed to “get the
right answer”. Since we don't have “mole-meters”, conversions to
or from moles are simply about the convenience of dealing with
quantities we can measure. These calculations are secondary to the
mole relationships indicated by the balanced chemical equation.
Molar volumes of gases and molar concentrations of solutions are
analogs to molar mass used in the previous unit. They enable one to
relate how much of a measured quantity to how many particles are
involved. The chemical potential energy involved in a reaction is
proportional to the number of particles involved. It may be
included as a term in the balanced equation for a reaction and
treated in the same manner as reactants and products in the BCA
table. DH is used as our best approximation of the change in Ech or
Eph.
Unit 10
Models of the
Atom
From an examination of the radiation emitted by hot metals and
atomic gases we conclude that atoms must have internal structure
not explained by Thomson's model.
Students are guided to examine the evidence that led us from
Thomson's model to Rutherford's nuclear atom and then to the
Bohr model of the atom.
We extend the Bohr model to many-electron atoms, using it to
Unit 11
PT and Bonding provide a structural explanation for the organization of the
Periodic Table, and to examine models of covalent bonding in
compounds.
Examination of sucessive ionization energies of the first 20
elements provides the evidence to enable us to develop a model of
atoms in which the arrangement of electrons is explained. We
move from a "valence model" to the Lewis model of covalent
bonding.
We know that when Ech of the system changes, the Eth also
Unit 12a
Particle model of changes, eventually resulting in a transfer of energy between the
temperature system and the surroundings. We adopt a "kinetic" view of
temperature to account for the direction of energy flow.
Unit 12b
The probable
direction of
change
We adopt a "probability" view to account for the direction of
processes involving both structural and thermal change.
Unit 13
Equilibrium
We return to a "kinetic" view to model a variety of processes as
they approach and reach the state of equilibrium.
We extend what we've learned about equilibrium to examine the
Unit 14
Acids and Bases Bronsted-Lowry model of acids and bases.