Chemistry

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Chemistry
Matter and Change
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Chemistry is
the study of the composition, structure, and
properties of matter and the changes it undergoes
C2H5OH 3 O2 ? 2 CO2 3 H2O Energy
Reactants ? Products
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Matter
Anything that has mass and occupies space
Mass
A measure of the amount of matter
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Atom
The smallest unit of an element that
maintains the properties of that element
Element
A pure substance made of only one kind of atom
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Compound
A substance that is made from the atoms of two or
more elements that are chemically bonded.
Sucrose C12H22O11
Sucrose is also known as table sugar, and is used
to make Gummy Bears!
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Properties of Matter
Extensive properties
depend on the amount of
matter that is present.
Volume
Mass
Energy Content (think Calories!)
Intensive properties
do not depend on the
amount of matter present.
Melting point
Boiling point
Density
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Physical Change
A change in a substance that does not involve a
change in the identity of the substance.
Example
Phase Changes
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Phase Differences
Solid definite volume and shape particles
packed in fixed positions.
Liquid definite volume but indefinite shape
particles close together but not in fixed
positions
Gas neither definite volume nor definite shape
particles are at great distances from one another
Plasma high temperature, ionized phase of
matter as found on the sun.
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Three Phases
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Copper Phases - Solid
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Copper Phases - Liquid
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Copper Phases Vapor (gas)
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Chemical Change
A change in which one or more substances are
converted into different substances.
Heat and light are often evidence of a chemical
change.
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Classification of Matter
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Separation of a Mixture
The constituents of the mixture retain their
identity and may be separated by physical means.
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Separation of a Mixture
The components of dyes such as ink may be
separated by paper chromatography.
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Separation of a Mixture
Distillation
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Separation of a CompoundThe Electrolysis of water
Compounds must be separated by chemical means.
With the application of electricity, water can be
separated into its elements
Reactant ? Products
Water ? Hydrogen Oxygen
H2O ? H2 O2
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The Periodic Table
Period
Group or Family
Group or family
Period
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Properties of Metals

• Metals are good conductors of heat and
  electricity
• Metals are malleable
• Metals are ductile
• Metals have high tensile strength
• Metals have luster

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Examples of Metals
Potassium, K reacts with water and must be stored
in kerosene
Copper, Cu, is a relatively soft metal, and a
very good electrical conductor.
Zinc, Zn, is more stable than potassium
Mercury, Hg, is the only metal that exists as a
liquid at room temperature
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Properties of Nonmetals
Carbon, the graphite in pencil lead is a great
example of a nonmetallic element.

• Nonmetals are poor conductors of heat and
• electricity
• Nonmetals tend to be brittle
• Many nonmetals are gases at room temperature

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Examples of Nonmetals
Microspheres of phosphorus, P, a reactive
nonmetal
Sulfur, S, was once known as brimstone
Graphite is not the only pure form of carbon, C.
Diamond is also carbon the color comes from
impurities caught within the crystal structure
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Properties of Metalloids
Metalloids straddle the border between metals and
nonmetals on the periodic table.

• They have properties of both metals and
  nonmetals.
• Metalloids are more brittle than metals, less
  brittle than most nonmetallic solids
• Metalloids are semiconductors of electricity
• Some metalloids possess metallic luster

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Silicon, Si A Metalloid

• Silicon has metallic luster
• Silicon is brittle like a nonmetal
• Silicon is a semiconductor of electricity

Other metalloids include

• Boron, B
• Germanium, Ge
• Arsenic, As
• Antimony, Sb
• Tellurium, Te