2. This lecture will help you understand:
• Chemistry: The Central Science
• The Submicroscopic World
• The Phases of Matter
• Physical and Chemical Properties
• Determining Physical and Chemical Changes
• Elements to Compounds
• Naming Compounds
3. Chemistry: The Central Science
Chemistry is the study of matter and the
transformations it can undergo.
5. Chemistry: The Central Science
• Chemistry is a "materials" science.
– Most of the material items in any modern
house are shaped by some human-devised
chemical process.
7. Chemistry: The Central Science
• More than 70% of all legislation placed before
the U.S. Congress addresses science-related
questions and issues.
8. The Submicroscopic World
• Roughly 250,000 dunes of this size contain
about 125 million trillion grains of sand.
• Yet, that's how many atoms there are in a single
grain of sand. (Atoms are small.)
9. What are atoms?
• Atoms are the smallest particles of matter
• Atoms make up everything around us
• Molecules are combinations of atoms
• Elements are only one type of atom
• Compounds are made up of different types of
atoms
10. The Phases of Matter
• One of the most evident ways
we can describe matter is by its
physical form, which may be
one of three phases (also
sometimes described as
physical states):
11. • The gaseous phase of any material occupies
significantly more volume than either its solid or
liquid phase.
• Frozen carbon dioxide, CO2, "dry ice"
The Phases of Matter
13. Physical and Chemical Properties
• A physical property describes the look or feel of
a substance.
14. Physical and Chemical Properties
• A chemical property describes the tendency of a
substance to transform into a new substance.
15. It is a chemical property of iron to transform into rust.
Physical and Chemical Properties
16. Physical and Chemical Properties
A physical change is a change in the physical
properties of a substance.
17.
18. • Chemical properties are properties that characterize
the ability of a substance to react with other
substances or to transform from one substance into
another.
Physical and Chemical Properties
19. • Any change in a substance that involves a
rearrangement of the way atoms are bonded is
called a chemical change.
Determining Physical and Chemical
Changes
21. Determining Physical and Chemical
Changes
• A physical change is a change in the physical
properties of a substance.
• A chemical change is the transformation of one
or more substances into others.
– A substance is identified not only by the kinds
of atoms it contains but also by how those
atoms are connected to one another.
– During a chemical change, a new substance
is formed as atoms rearrange themselves into
new configurations.
22. Determining Physical and Chemical
Changes
• A physical change imposes a new set of
conditions on the same material.
• A chemical change forms a new material that
has its own unique set of physical properties.
• Both physical and chemical changes result in a
change in physical appearance.
24. Physical or chemical change?
Ammonium
dichromate
Ammonium dichromate + Heat Ammonia,
water,
chromium
(III) oxide
25. • An element is a material made of only one kind
of atom. Pure gold is an element because it is
made of only gold atoms.
• An atom is the fundamental unit of an element.
• The term "element" is used when referring to
macroscopic quantities.
• The term "atom" is used when discussing the
submicroscopic.
Elements to Compounds
26. Compound Formula
Oxygen O2
Ozone O3
Sulfur S8
Gold Au
Elements to Compounds
• The elemental formula is used to show the
proportion by which atoms combine to form an
element.
27. Elements to Compounds
A compound is a substance
that consists of atoms of
different elements.
28. Elements to Compounds
• Compounds have properties uniquely different
from the elements from which they are made.
29. Compound Formula
Sodium chloride NaCl
Ammonia NH3
Water H2O
Elements to Compounds
• A chemical formula is used to show the
proportion by which elements combine to form a
compound.
30. • Guideline 1
– Start with the element farthest to the left in the
periodic table.
– For the element to the right, add the suffix -ide.
Example:
NaCl
Naming Compounds
