Download 2 - Del Mar College

Unit 1: Matter & Energy
• Description
• Measurement
• SI - Metric
System
CHEM 1411, revised 10 Aug 2007
• Conversions
• Thermodynamics
Definition - Matter
• Anything the has mass and can
be detected and measured,
made up of atoms and may
be a solid, a liquid, gaseous
or a plasma
The
The Nature
Nature of
of Matter
Matter
Gold
Mercury
Chemists are interested in the nature of
matter and how this is related to its atoms
and molecules.
• An atom is the smallest particle of an
element that has the chemical
properties of the element.
Copper
atoms on
silica
surface.
Distance across = 1.8 nanometer (1.8 x 10-9 m)
Chemistry & Matter
• We can explore the
MACROSCOPIC world — what we
can see —
• to understand the PARTICULATE
worlds we cannot see.
• We write SYMBOLS to describe
these worlds.
Conservation
• Conservation of
Matter - matter is
neither created
nor destroyed
must account for
all matter during a
reaction
• Conservation of
Energy - energy
is neither created
nor destroyed,
changed from one
form to another
must account for
all energy
• SOLIDS — have rigid shape, fixed volume.
External shape can reflect the atomic and
molecular arrangement.
– Reasonably well understood.
• LIQUIDS — have no fixed shape and may
not fill a container completely.
– Not well understood.
• GASES — expand to fill their container.
Good theoretical understanding.
Fig. 1.2, p.13
Fig. 1.1, p.12
Matter Classification
Element
• Pure substance that cannot be
decomposed any further by ordinary
means
• About 115 elements listed on Periodic
Table
metals, non-metals, metalloids,
atomic number, atomic symbol
Element - definition
• An element is a type of matter
composed of atoms that all have
exactly the same positive charge on
their nuclei. In other words, all atoms
of an element have the same atomic
number .
http://antoine.frostburg.edu/chem/senese/101/matter/faq/what-is-an-element.shtml
Periodic Table
• Dmitri Mendeleev developed the
modern periodic table. Argued
that element properties are
periodic functions of their atomic
weights.
• We now know that element
properties are periodic functions of
their ATOMIC NUMBERS.
Short Form of Periodic Table
Long Form-Periodic Table
p.79a
p.79b
Regions of the Periodic Table
Group 1A: Alkali Metals
Li, Na, K, Rb, Cs
Cutting sodium metal
Group 2A: Alkaline Earth Metals
Be, Mg, Ca, Sr, Ba, Ra
Magnesium
Magnesium
oxide
Group 7A: Halogens
F, Cl, Br, I, At
Group 8A: Noble Gases
He, Ne, Ar, Kr, Xe, Rn
Group 6A: O, S, Se, Te, Po
Sulfuric acid dripping
from snot-tite in cave
in Mexico
Elemental S has a ring
structure.
Transition Elements
Lanthanides and
actinides
Iron in air gives
iron(III) oxide
Forms of the Elements
• Most are monoatomic – a single atom is the
element, examples: Zn (s), Al (s), Cs (s)
• Some are Diatomic – two atoms bound
together form the element (not single atom
shown of Periodic Table)
H2 (g); N2 (g); O2 (g); F2 (g); Cl2 (g);
Br2 (l); I2 (s);
Compound
• Pure substance composed of two or more
elements bonded together in a definite ratio
by weight.
Identified by a unique set of physical
and chemical properties.
H2O and H2O2
Na2CrO4 and Na2Cr2O7
Compound - definition
• Water – H2O
2 atoms of hydrogen
bound to 1 atom of
oxygen
• Hydrogen Peroxide –
H2O2
2 atoms of hydrogen
bound to 2 atoms of
oxygen
ALL water molecules
are 11.19 % H by
weight and 88.81%
oxygen by weight
• H2O2 5.93% H by
weight and 94.07 %
oxygen by weight
Comparison of Physical Properties
Water and Hydrogen Peroxide
Water
Hydrogen
peroxide
Melting point
°C
0.0
-2
Boiling point
°C
100
158
Density, g/mL
1.0
1.46
Compounds
• Same three component elements – Na, Cr, O
but different weight ratios
Na2CrO4
Na2Cr2O7
Terms for Matter
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Heterogeneous
Homogeneous
Mixture
Solution
Physical process
Chemical process
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•
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Element
Compound
Atom
Solid
Liquid
Gas
Classification of Energy
Description of Energy
Energy
Potential
Kinetic
(position or stored)
(motion)
Potential
Potential &
& Kinetic
Kinetic Energy
Energy
Potential
energy —
energy a
motionless
body has by
virtue of its
position.
Potential
Potential &
& Kinetic
Kinetic Energy
Energy
Kinetic energy
— energy of
motion
• Translation
Potential Energy
on the Atomic Scale
• Positive and negative
particles (ions) attract
one another.
• Two atoms can bond
• As the particles
attract they have a
lower potential
energy
NaCl — composed of
Na+ and Cl- ions.
Potential Energy
Potential energy is stored energy and the energy of position––There are
several forms of potential energy.
Chemical Energy is energy stored in the bonds of atoms and
molecules. It is the energy that holds these particles together. Biomass,
petroleum, natural gas, and propane are examples of stored chemical
energy.
Stored Mechanical Energy is energy stored in objects by the
application of a force. Compressed springs and stretched rubber bands
are examples of stored mechanical energy.
Nuclear Energy is energy stored in the nucleus of an atom––the
energy that holds the nucleus together. The energy can be released
when the nuclei are combined or split apart. Nuclear power plants split
the nuclei of uranium atoms in a process called fission. The sun
combines the nuclei of hydrogen atoms in a process called fusion.
Scientists are working on creating fusion energy on earth, so that
someday there might be fusion power plants.
Gravitational Energy is the energy of position or place. A rock
resting at the top of a hill contains gravitational potential energy.
Hydropower, such as water in a reservoir behind a dam, is an example
of gravitational potential energy.
Kinetic energy — energy of
motion.
rotate
vibrate
translate
Kinetic Energy
Kinetic energy is motion––of waves, electrons, atoms, molecules, substances, and
objects.
Electrical Energy is the movement of electrical charges. Everything is made
of tiny particles called atoms. Atoms are made of even smaller particles called
electrons, protons, and neutrons. Applying a force can make some of the
electrons move. Electrical charges moving through a wire is called electricity.
Lightning is another example of electrical energy.
Radiant Energy is electromagnetic energy that travels in transverse waves.
Radiant energy includes visible light, x-rays, gamma rays and radio waves.
Light is one type of radiant energy. Solar energy is an example of radiant
energy.
Thermal Energy, or heat, is the internal energy in substances––the vibration
and movement of the atoms and molecules within substances. Geothermal
energy is an example of thermal energy.
Motion Energy is the movement of objects and substances from one place to
another. Objects and substances move when a force is applied according to
Newton’s Laws of Motion. Wind is an example of motion energy.
Sound is the movement of energy through substances in longitudinal
(compression/rarefaction) waves. Sound is produced when a force causes an
object or substance to vibrate––the energy is transferred through the substance
in a wave.
ENERGY is the capacity
to do work or transfer
heat.
HEAT is the form of
energy that flows
between 2 objects
because of their
difference in temperature.
Other forms of energy —
•light
•electrical
•kinetic and potential
Forms of Energy
Energy
Heat
Light
Electricity
Definitions
• Heat – a measure of the amount of
energy transferred from one body
to another because of the
temperature difference between
those bodies
Definition
• Electromagnetic Radiation (light) –
interacting electric and magnetic
waves that propagate through a
vacuum at 3 X 108 m/s, includes
gamma rays, ultraviolet , visible
light, infrared, radio waves
Planck’s Equation
• E = hc
λ
h is a constant value
c is the speed of light in a vacuum
λ is the wavelength of
electromagnetic radiation
Definition
• Electrical Energy – energy of
charges ( + or - ) as a result of
position or motion
Dissimilar charges attract
Similar charges repel
Thermodynamics
• Thermodynamics is the science of
heat (energy) transfer.
• Heat transfers until thermal
equilibrium is established.
Terms for Energy
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Kinetic Energy
Potential Energy
Heat
Light
Thermodynamics
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Plank’s Equation
Electrical Energy
Wavelength
Thermal
Equilibrium