Chemistry Notes: Chapter 1
Chemistry—the study of the composition, structure and properties of matter and the
changes it undergoes.
Branches of Chemistry:
1. Organic—study of most carbon containing compounds.
2. Inorganic—the study of all substances not considered organic. Most are
compounds that do not contain carbon.
3. Physical—study of the properties and changes of matter and their relationship
to energy.
4. Analytical Chemistry—identifying the components and composition of
materials.
5. Biochemistry—study of substances and processes occurring in living things.
6. Theoretical—use of mathematics and computers to understand the principles
behind observed chemical behavior and to design and predict the properties of
compounds.
Chemical—any substance that has a definite composition. Knowing the properties of
chemicals allows chemists to find suitable uses for them.
1-2 Matter—anything that has mass and takes up space.
Mass—measures the amount of matter in an object.
Volume—amount of 3 dimensional space an object takes up.
Atom—smallest unit of an element that maintains the properties of the element.
Pure Substance: either an element or a compound. Everything else is a mixture.
Element—pure substance made of only one kind of atom. Examples: carbon, oxygen,
hydrogen. All elements can be found on the periodic table. All elements can be
identified by a symbol.
Compound: substance made up of two or more elements chemically combined. Ex.
Water, sugar, salt. All compounds can be identified by a formula.
Some compounds consist of molecules. A molecule is the smallest unit of an element or
compound that retains all of the properties of that element or compound. Only
nonmetals comprise molecules. Ionic compounds will never form molecules.
Properties: a characteristic that defines an entire group of substances.
Extensive properties—depend on the amount of matter that is present such as
volume, mass and energy content.
Intensive properties—do not depend o the amount of matter present such as
density, melting point or boiling point.
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Physical Property—characteristic that can be observed without changing the
identify of the substance e such as a change of state ( melting, boiling) color, shape)
Physical change—a change that does not change the identity of the
substance such as boiling, melting, cutting, bending.
Chemical Property—relates to a substance’s ability to undergo changes that
transform it into different substances. Examples: burning, decaying, rusting.
Chemical change—change in which a substance is changed into one or
more different substances. Examples: burning, rusting, souring, photosynthesis.
States of Matter—
Solid—def. volume, def shape
Liquid—definite volume, take the shape of the container and may have one free surface.
Gas—no definite volume, no definite shape, cannot have a free surface.
Plasma—high temperature physical state made up of charged particles resulting from the
gain or loss of electrons.
Law of Conservation of Energy—Energy cannot be created or destroyed. It can only
change form.
Endothermic—energy is gained (photosynthesis)
Exothermic—energy is released (burning)
Matter can be classified into two main groups:
1. Pure substances (either an element or a compound)
fixed composition
every sample has the same composition and characteristics
2. Mixture A blend of two or more kinds of matter, each of which retains its own
identity and properties. If it isn’t an element or a compound, it is a mixture.
Homogenous mixture—uniform composition with the same properties
throughout. (salt water, air)
Heterogenous mixture—not uniform. Does not have the same properties
throughout. (vegetable soup, Dairy Queen blizzard)
Filtration can be used to separate some mixtures. Also, a centrifuge can be used to
separate some solid/liquid mixtures such as blood. Chromatography can be used to
separate mixtures of liquids.
1-3 Periodic Table
Organizes all the elements.
1. Vertical columns are groups or families.
Groups number form 1-18. Each group contains elements with similar properties.
2. Horizontal rows are called periods. The properties of a period change somewhat
regularly across the period starting from very active metals and ending with a noble gas.
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3. Lanthanide series—fits in the group 6 elements
4. Actinide series—fits in with group 7 elements.
They are placed below the periodic table to keep the table from becoming too wide.
Types of elements—
1. Metals—elements that are good conductors of heat and electricity.
a. they are ductile (can be stretched into a thin wire.
b. they are malleable (can be hammered into thin sheets)
c. they are good conductors of heat and electricity.
d. most have a silvery or grayish white luster.
e. they are located on the left side of the periodic table.
f. most are solids are room temperature.
2. Nonmetals—can be gases, liquids, or solids at room temperature.
a. poor conductors of heat and electricity
b. they are brittle
c. found on the right side of the periodic table.
3. Metalloids—elements that have some characteristics of metals and some
characteristics of nonmetals.
a. all of solid at room temperature
b. found along the zig zag line
c. many are semiconductors of electricity.
4. Noble Gases: generally very unreactive
a. Located in group 18
b. all are gases at room temperature
c. Neon, argon, krypton and xenon are all used in lighting.
d. Helium is used in balloons.
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