Intro to Chemistry
Chapter 1 and Chapter 2
A Preview of Coming Attractions
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RIGOROUS
ONLY INTENDED FOR MATURE STUDENTS!
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The Ancient Greeks
~ 400 BC
S Aristotle suggested that everything was composed of 4
elements:
S Water, Air, Earth and Fire
S He later added a 5th element which he called “aether” which
the stars and the heavens were made from.
S Aristotle also said that “cold” was a substance he called
primum frigidum, and that “cold” came from water.
S People actually believed this up until the middle ages (1500s at
least).
S Click on the next slide to see three of these “ancient elements.”
Earth Wind & Fire
(http://www.earthwindandfire.com/bio.html)
Yes, I’m “old school.” But I love these guys. And, I even saw them
in concert once, back in the 80’s. OK, back to chemistry on the
NEXT slide…If you don’t some Earth Wind and Fire on your
“playlist,” get some. Tonight. Seriously.
Notes are not
optional!
CUES
1-2
words
CUES
Main part for Notes
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. Use bullet points
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.. Abbreviate
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. Draw pictures to
. help you.
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. You do not have
. to write in
. complete
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Main Part for Notes
The Law of
Conservation of Mass
S In any chemical reaction or physical change, matter can
neither be created nor destroyed (page 50)
S The amount of matter (mass) doesn’t change.
S However, the identity of the matter (what type of
substance it is) could change.
S mass of the reactancts = mass of the products (this is a
statement of the law in math form, using an equation)
Chapter 2. Big Idea =
Chem as a Central Science
S Back to matter…matter has mass and volume.
S Intensive property—depends on the type of matter.
S Extensive property—depends on the amount of matter.
S Matter can be broken down into substances and mixtures.
S Substances are pure.
S Elements (smallest part of an element is an atom)
S Compounds (smallest part of a compound is a molecule)
S Mixtures of substances. NOT bonded together.
S Mixtures are either homogeneous or heterogenous.
Physical Properties
S Matter has both physical and chemical
properties.
S Physical properties can be observed without
CHANGING the type of matter.
S When solid water (ice) melts it becomes liquid
water. A change of state is a physical change (Δ or
delta means change).
S Physical changes are NOT permanent and are
reversible.
Chemical Properties
S Chemical properties can be ONLY be
observed BY CHANGING the type of
matter.
S Chemical properties are permanent and not
reversible.
S When salt is dissolved in water, a solution is
formed. That is a physical change. The salt is
still salt and the water is still water. You can
separate them easily by evaporating the water.
Chemical Properties
S But when sodium oxide (Na2O) is dissolved in water it
dissolves, but then a chemical reaction occurs. That is a
chemical change.
S Sodium oxide has different chemical properties compared to salt, and
so it reacts differently.
S We write the reaction as
Na2O + H2O  2 NaOH
S That’s your first chemical “sentence.” The reaction describes a
chemical change. You need to be able to identify a property or
change as being either chemical or physical for the first test!
States of Matter
S Solid *
S Liquid *
S Gas *
S A vapor is a substance that is generally solid or liquid at room temperature,
but is in the gaseous state (like steam or water vapor).
S You don’t need to know these, but they do exist:
S Plasma
S Only observed at extremely high temperatures (several thousand degrees)
S Bose-Einstein condensates and Fermionic condensates
S Only observed at extremely low temperatures (within a degree or less of
absolute zero). Being investigated at University of Colorado.
Substances vs mixtures
S Carbon is a substance.
S Water is a substance.
S Air is a mixture of substances (O2, N2, CO2,
etc)
S It is a homogenous mixture.
S What is the 3rd most abundant component of
the air you breathe?
S A salad is a heterogeneous mixture.
Substances vs mixtures?
S You try some
S Methane (natural gas)
S Coffee
S Copper
S Salt
S Dirt
S Sand
What are physical separation
techniques? Techniques for
separating mixtures.
S Evaporation—can separate DISSOLVED solids from
the liquid.
S Filtration—can separate UNDISSOLVED solids from
the liquid.
S Decanting—can separate a dense solid from the liquid
(because the solid is on the bottom and you can pour
off the liquid).
S Distillation—can separate a mixture of liquids by
boiling them and condensing the vapors (check out the
distillation apparatus at the bottom of pg 40).
A physical separation technique
sometimes tested on the SOL.
S Chromatography
S Can be used to
separate a mixture of
solids dissolved in a
liquid.
S Ink
S Natural dyes
S Not in Chap 2, but
you better know it!!
Substances: Elements
S Elements are on the Periodic Table. 90 occur naturally (1-92
except for 43Tc and 61Pm). 118 elements exist (but 113 Uut,
115 Uup, 117 Uus, 118 Uuo have not been named yet).
S Elements 93 and higher are man made (most of them by Dr.
Glenn Seaborg and his team at U. California @ Berkeley)
S 119 (Uue) and 120 (Ubn) are currently being worked on but
have not been synthesized as of yet.
S http://www.youtube.com/watch?v=cma-AjOUplU
S Do any still “undiscovered” elements exist anywhere in the
Universe?
Substances: Compounds
S Compounds are pure substances too. There are
literally millions of chemical compounds. Some
common compounds are:
S
S
S
S
S
S
S
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Salt (sodium chloride or NaCl)
Sugar (sucrose or C12H22O11)
Baking Soda (sodium bicarbonate or NaHCO3)
Sand (silicon dioxide or SiO2)
Rubbing Alcohol (isopropanol or C3H7OH)
Carbon dioxide (CO2)
Ammonia (NH3)
Methane (CH4)
Distinguishing between:
Elements, Compounds, and
Mixtures?
S How can you tell if it’s an element or a compound or
mixture?
S An element cannot be broken down into anything simpler.
S A compound can be separated into smaller elements.
S But, you must use a chemical reaction to break down a
compound, because the elements in a compound are bonded
together.
S A mixture can be separated using physical separation
techniques.
S Check out the cool flowchart at the bottom of page 44.
Ionic Compounds vs
Molecular Compounds
S There are 2 types of compounds
S Ionic compounds have ionic bonds and are
composed of positive and negative ions.
S Ions are formed when atoms lose or gain
electrons.
S Molecular compounds have covalent bonds.
S Electrons are shared between atoms. There are
no ions or charges.
S We will study this more in Chapter 9.
Chemical Reactions
S Reactants  Products
S You need to start with 1 or more reactants and
You will produce 1 or more products
S How many you need and how much you produce
is characteristic of the specific reaction.
S We will study 5 major types of reactions starting
in Chapter 11.
S Chemical reactions are PERMANENT and NOT
reversible.
That’s Chemistry…
S That’s really all chemistry is…
S Atoms either take electrons from other atoms or
S Atoms lose electrons to other atoms or
S Atoms share electrons with other atoms
S Bonds are broken during that process and new bonds
are formed.
S Chemistry is the interaction of my electrons with your
electrons to form a bond. Electrons are involved, not
the protons or neutrons.
The End