Do Now
February 16th 2011
Which of the following is NOT an example
of matter?
Sunglasses
Beach towel
Sunlight
Water
Which of the following states has
DEFINITE shape and volume?
Solid
Liquid
Gas
Plasma
SWBAT describe the difference
between an element and
compound.
Elements, Compounds,
and Mixtures
3 KINDS OF MATTER
Elements
Compounds
Mixtures
Elements
All (living and nonliving) of the different
kinds of matter in the universe is made
from about 100 different substances,
called elements.
Elements are called the building blocks of
matter because all matter is composed of
elements.
Each element is made up of the same type
of atoms.
Compounds
 A compound is a substance made of two or
more different kinds of elements chemically
combined in a specific ratio.
 Each compound is represented by a formula that
uses symbols to identify which elements are
present.
 A formula shows the ratio of elements in the
compound.
 H2O – ratio of Hydrogen is 2:1 Oxygen
The symbols make up the formula. A
formula is just chemical shorthand for the
compound.

The subscript lets us know how many
atoms are present.

The coefficient lets us know how many
molecules are present.
Compounds
Molecules
A molecule is formed when two or more
atoms join together chemically.
Diatomic molecules are made of two
atoms of the same element.
Hydrogen – H2
Oxygen – O2
What is the difference between a
compound and a molecule?
A molecule is formed when two or more
atoms join together chemically.
A compound is a molecule that contains at
least two different elements.
All compounds are molecules but not all
molecules are compounds.
Molecular hydrogen (H2), molecular
oxygen (O2) and molecular nitrogen (N2)
are not compounds because each is
composed of a single element.
Water (H2O), carbon dioxide (CO2) and
methane (CH4) are compounds because
each is made from more than one
element.
Molecule
The smallest bit of each of these
substances would be referred to as a
molecule. For example, a single molecule
of molecular hydrogen is made from two
atoms of hydrogen.
A single molecule of water is made from
two atoms of hydrogen and one atom of
oxygen.
Worksheet Practice
Number of
Number of
elements
atoms per element
H2SO4 ______ ____________________
Elements in compound:
__________________________________
Cr(NH3)6(NO3)3 _______ ____________
Elements in compound:
__________________________________
__________________
Classwork/Homework
Classwork
Complete the element VS. compound worksheet
Homework
Chapter 2 Section 1
Complete Review Questions
Page 44
Questions # 1  7