Unit #2
Intro to Chemistry, Branches of Chemistry,
Scientific Method, & Matter.
AlchemyAncient practice in which the "scientist"
attempted to turn common metals into gold.
WE KNOW THIS IS IMPOSSIBLE, but they did
not. However, they did help science in that they
discovered chemicals, designed lab equipment,
and even "discovered" how to separate mixtures
by distillation and sublimation.
ChemistryThe study of the composition of
substances and the changes they
undergo.
Antoine Lavoiser"Father" of modern chemistry.
He made and recorded changes of mass
during chemical reactions.
Chemistry is all around us.
You live with it and its products on
a daily basis.
Can you think of any examples?
Synthetic fibers -
Nylon, Rayon, Spandex, Polyester…
Clothing dyes
Hair coloring
Nail polish remover
Soaps
Calculators, iPods, Cell phones…
Crude oil and its derivatives.
Many others…
Major Branches (types) of
Chemistry
Organic ChemistryThe study of essentially all substances containing
carbon; deals with the "SPONCH" elements.
SPONCH- an acronym made of the element
symbols of: Sulfur, Phosphorus, Oxygen, Nitrogen,
Carbon, & Hydrogen.
Often used by: Chemical engineers (creators of tire
compounds, insecticides, synthetic lubricants…),
Lab technicians, Medicine inventors…
Organic Chemistry (con’t) Examples: Synthetic fibers
Non-stick cooking surfaces (Teflon)
Tires…
Physical ChemistryThe study of chemicals and the changes in
energy as they undergo reactions and processes.
Examples:
Balloons
Automobile engineers
Explosive designers
Energy =
1. work, 2. heat, 3. entropy (vibration
and wasted energy (disorder)).
Inorganic ChemistryThe study of substances without carbon;
mainly from non-living things.
Examples: Minerals
Gemology
Metal manufacturing
Alloys
Generally anything not “SPONCH”
Analytical ChemistryConcerned with the composition of substances.
There are two types: Qualitative and Quantitative.
Examples: Soil testing
Water testing
Blood analysis.
Qualitative Analytical Chemistry Determines if a substance is present by
testing for its characteristic reactions with
certain substances.
Examples: Test for Lead paint
Tests for “banned” substances
Indicates only the presence of something
Quantitative Analytical Chemistry Determines how much of a substance is
present; its quantity; ("Percent composition").
Examples:
Blood Alcohol Test
Testing for Sugar in diabetic blood
Testing for pH in swimming pools
BiochemistryThe study of the chemistry of living things and
their processes.
Examples: Photosynthesis
Respiration
Marine biology
Digestion
WMD (Biological or chemical weapons)
Some other Natural Sciences that
involve Chemistry:
1) Geology: The study of the earth.
Examples:
Petroleum, distillation of crude oil, mining and
how much sulfur may be in the coal.
Some other Natural Sciences that
involve Chemistry (con’t):
2) Biology: The study of the life.
Examples:
How body processes function, detoxification of
poisons (including medicines), respiration, and
photosynthesis.
Some other Natural Sciences that
involve Chemistry (con’t):
3) Physics: The study of energy and forces.
Examples:
Electronics, circuit boards, computer chips,
diodes…
Two types of Chemistry 1)
Pure Chemistry
2)
Applied Chemistry
Pure ChemistryKnowledge is accumulated for its own
sake; neither good nor bad.
Examples:
Chemical reactions, how much, what is it,
color?, texture…
Applied ChemistryKnowledge is either used to benefit or
harm people or the environment.
Examples:
Medicine, chemical warfare, cloning.
The Scientific Method A series of steps used to solve problems.
5 steps of the Scientific Method:
1)
Observe the problem.
“What’s wrong?”
5 steps of the Scientific Method
(con’t):
2)
Hypothesize the reason.
Ask questions to find out why there
is a problem.
5 steps of the Scientific Method
(con’t):
3)
Experiment
To test your hypothesis.
5 steps of the Scientific Method
(con’t):
4)
Analyze
Did the experiment prove your
hypothesis correct?
If not… go back to the hypothesis
step.
5 steps of the Scientific Method
(con’t):
5)
Conclude / Theorize
Conclude why the problem
occurred.
Theory vs. Law
TheoryA thoroughly tested explanation of
why experiments give certain results.
LawA concise statement that
summarizes the results of a broad
spectrum of observations and
experiments.
What is the difference between a
theory and a law?
A theory explains why experiments
give results. A law describes the results
of observations.
Matter
Matter Anything that takes up space and has a
mass.
Mass Amount of matter in an object.
Weight Effect of gravity on matter.
What is the difference between
mass and weight?
Assume a jar of peanut butter weighs 600 g.
(1.32 pound) on earth. The moon's gravity is 1/6th that
of the earth's; therefore the same jar would weigh only
100 g. (0.22 pound) on the moon. That is weight.
However, did the mass change ? (Assume it was
never opened.) No. That is mass (the amount of
matter).
All matter belongs
to one of two groups of matter:
1)
Heterogeneous matter
2)
Homogeneous matter
Heterogeneous matterMatter that is different or not
uniform in composition; each type of
substance retains its own unique
properties, and each can be separated
from the other by ordinary chemical
means. These are all mixtures.
Examples of Heterogeneous Matter:
M&Ms
Tossed salad
Lucky Charms
Jell-O fruit salad…
Homogeneous matterMatter that is uniform in
composition.
Examples of Homogeneous Matter:
Oxygen
Water
salt water
kool-aid
Aluminum
Iron
Carbon dioxide
tomato soup
Juice
These may be either mixtures (specifically
solutions) or pure substances.
Mixtures A general type of matter that may
be either heterogeneous or
homogeneous. (They are a physical
blend of two or more substances.)
All homogeneous matter belongs to
one of two groups:
1)
2)
Pure substances
Solutions
Pure substancesA particular kind of matter with a definite
and uniform composition.
Examples: Water
CO2
Oxygen
Lead
Americium
SolutionsHomogeneous mixtures.
Examples: Salt water
Orange juice…
Solutions have phases that are either solid, liquid,
gas, or a combination of the three.
They are always listed with the lesser constituent first.
All solutions are a mixture of the solute
and solvent.
Solute- The substance that is dissolved. It is the
lesser constituent by volume.
Example:
The “Salt” in saltwater.
SolventThe substance that does the dissolving. It is
the greater constituent by volume.
Example:
The water in saltwater.
There are 6 types of solutions based on
the phases of their components.
Remember: The components are always listed
with the solute first, followed by the solvent.
1) Gas - Gas
Examples:
Oxygen in the air.
Recall the composition of “Air”
75% Nitrogen
20% Oxygen
4% Carbon dioxide
1% Argon and all others.
100% Air
2) Liquid - Gas
Examples:
Water vapor in the air.
3) Gas - Liquid
Examples:
Carbon dioxide in water.
4) Liquid - Liquid
Examples:
“2 - Stroke Fuel”
(Oil in Gas).
5) Solid - Liquid
Examples: Sugar / flavoring in water (“Kool-aid”)
6) Solid - Solid
Examples: Alloys:
1. (Copper in Silver, “Sterling Silver”)
2.
A homogeneous solution has only
one phase (“Kool-aid”), while a
heterogeneous solution has 2 or more
phases. (Vinegar & Oil).
All pure substances belong to one of two
groups:
1)
Elements
2)
Compounds
Elements A substance that cannot be decomposed by
ordinary physical or chemical means, under
normal laboratory conditions. Each has its own
unique and identifiable characteristics.
Examples:
Anything on the periodic table.
Compound A chemical combination of elements. Each has
its own unique and identifiable characteristics. Cannot
be separated by physical means. Can be separated
by chemical means.
Examples:
NaCl, H20, CO2
There are two main groups of
elements:
1)
2)
Metals
Non-metals
MetalsElements that are usually solid / liquid at
room temperature, good conductors of heat and
electricity, malleable, ductile, often shiny (luster).
Examples:
Magnesium
Sodium
Iron
Non-metals Elements that may be either solid, liquid, or
gaseous, poor conductors of heat and
electricity, brittle, and often dull.
Examples:
Argon
Sulfur
Iodine
Two specific types of non-metals
are:
1)
Metalloids
2)
Gases
MetalloidsNon-metals with some metal like properties.
Often used in electronics.
Examples:
Silicon
Arsenic
Boron
Gases Elements that are "gases". They are matter
with no definite shape or volume, are fluid (they
"flow").
Examples:
Oxygen
Helium
Radon
Compound Remember-
A compound is a chemical combination of
elements. Each with its own unique and identifiable
characteristics. They cannot be separated by physical
means, but can be separated by chemical means.
Another example:
Na is explosive when wet
Cl2 is a poisonous gas.
When combined, they produce the compound
known as Sodium chloride ("table salt”).
Law of Definite CompositionAll compounds have a definite
composition by mass.
Example:
Water has a mass of 18g. / mole.
Of those 18 grams, 11.1% are always from the Hydrogen.
The remaining 88.9% are from the Oxygen.
Matter
Homogeneous
Heterogeneous
Solutions
Compounds
Mixtures
Metals
Pure substances
Elements
Non-metals
Others
Physical propertyA quality or condition of a substance that
can be observed or measured without
changing its composition. The value does not
change with the amount of substance.
Examples:
1)
2)
3)
4)
5)
6)
7)
8)
9)
Density
Boiling / Condensation point
Melting / Freezing point
Color
State
Odor
Texture
Solubility
Hardness
Chemical propertyThe ability of a substance to undergo
a chemical reaction (a change) and
form a new substance with new, unique
properties.
Physical changeAltering a substance without changing its
composition, physical or chemical properties.
Examples:
Grinding
Melting / Freezing / Boiling
Chopping…
Chemical changeAlters a substance by changing its composition.
Examples:
Combustion of hydrogen to produce water
Oxidation of iron to make "rust"
Decomposition of carbonic acid to make water
and CO2.
The States of Matter.
Identify each drawing below as either a gas, liquid, or a solid
Solid
Liquid
Gas
SolidMatter with a definite shape and
volume. (Low energy and entropy).
LiquidMatter without a definite shape, has
a definite volume, "flows", takes the
shape of the container as it fills it from
the bottom up. ("Moderate" energy &
entropy).
GasMatter without a definite shape or
volume. (High energy & entropy).
FluidAny matter that flows. Includes both
liquids and gases.
LiquidMatter without a definite shape, but
with a definite volume. Does not include
gases.
Fluid
Liquid
VaporDescribes a substance that although it is in a
gaseous state (like a gas), is either a liquid or a solid at
room temperature.
Examples: Steam
Gasoline vapor in an internal combustion
engine.
Sodium vapor in street lights
Xenon vapor in HID headlamps,
GasMatter without a definite shape or
volume. (High energy & entropy).
Examples: Oxygen
Helium
Radon
Gas
Vapor
Processes in nature are driven two ways:
1) Toward lowest energy.
2) Toward greatest entropy.
Entropy -
The amount of disorder in a system.
Ga s
Condensat ion
Decreasing Entropy & Energy
Cooling
Liquid
Evaporating
Freezing
Melting
Solid
Increasing Entropy & Energy
Warming