helps understand better about the elements molecules and mixtures

1. Elements, Compounds, and
Mixtures

2. The better classification is
there are 3 constituents of MATTER
Elements
Compounds
Mixtures

3. Elements
All kinds of matter in the universe is made
from about 117 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.

4. 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

5. 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.

6. CompoundsCompounds

7. 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

8. 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.

9. 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.

10. 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.

11. Mixtures
Most matter in the
universe is found in
mixtures.
A mixture is made
from two or more
substances either
elements, compounds
or both - that are not
chemically combined.

12. Mixtures and
compounds differ
in two ways…
Substances in a mixture keep
their individual properties.
Parts of a mixture are not
necessarily present in specific
ratios.

13. Compounds and Mixtures
Most of the matter around you is in the
form of compounds or mixtures.
Water, carbon dioxide, salt, vinegar,
baking soda, sugar are all chemical
compounds.

14. NaCl is the formula for salt
It is a compound.

15. Water is H2O
An oxygen atom can bond
with two hydrogen atoms to
make a molecule we call
water. Water is an example of
a compound, because it
contains more than one kind
of atom. The formula for
water is H2O, meaning there
are two hydrogen atoms for
each oxygen atom.

16. Carbon Dioxide CO2
Carbon dioxide molecules are made from
one carbon and two oxygen atoms joined
together. The chemical symbol is CO2

17. Molecule
When a compound is broken down into its’
smallest piece it is called a molecule. You
should be able to write the formula for the
following:
Water
Oxygen
Carbon Dioxide