Download Elements, Compounds and Chemical Reactions

Elements,
Compounds and
Chemical Reactions
(Chemical Reactions Song)
Element
Definition: A pure
substance made up of
only one kind of atom!
An atom is the basic
unit of an element.
The Periodic Table
lists all the known
elements
The Earth is Made of Elements!
• While the Periodic Table is HUGE, just a few
of those elements make up most of our
Earth. Take a look at these pie graphs!
The Earth is Made of Elements
• From these last two pie charts, you should
be able to see that our air is mostly Nitrogen,
then oxygen, our crust is mostly oxygen and
then silicon, and our bodies are oxygen and
then carbon.
• Add in the Hydrogen from water, and that’s
only 5 elements out of 118 that make up
most of what we know!
Element Cube
On the Periodic Table, each
element has an element cube that
gives information about the
element. The symbol is the short
name for the element. Notice that
for an element, there is only ONE
capital letter! Sometime the
chemical symbol doesn’t look like
it comes from the name of the
element. This happens when the
symbol comes from the Latin
Compound
A pure substance
made up of two or
more different
elements! Compounds
contain two or more
capital letters, and are
made up of molecules.
Cl
Na
What do you use
this compound for
in life?
Molecule
A particle of matter in which one
or more elements are joined
tightly together.
Hydrogen
Hydrogen
Oxygen
Molecules are the basic unit of a
compound.
What is the name for this
abundant molecule on Earth?
Physical Properties
Elements and compounds
have both PHYSICAL and
CHEMICAL properties. A
property that can be observed,
measured or changed without
changing the substance itself
is called a physical property.
Physical Properties Examples:
•
•
•
•
•
•
Odor (Smell)
Color
Mass
Volume
Density
Texture
How are these observed
or measured?
Chemical Properties
Chemical properties cannot be changed without
creating a new substance. Whenever a chemical
property is changed, the result will be a new
substance with new chemical properties. For example:
=
+
Poisonous
Explosive
Gas
Powder
Table
Salt
CHEMICAL
REACTION!
A process in which one or more
substances are changed into others.
In a chemical reaction,
a new substance is always formed!
Click here to see some examples!
Examples of Chemical
Reactions
SIGNS OF A CHEMICAL
REACTION
• We use the phrase ‘Please Excuse Coughs,
Burps, and Sneezes’ to help remember the
signs of a chemical reaction. Each capital
letter stands for one of the signs. Let’s look
at each one.
Evidence of
Chemical Reactions
•PLEASE- Precipitate Formed
•A precipitate can form
when one liquid is poured
into another and a solid
forms. The best known is
when milk is poured into
vinegar, a solid is created.
Evidence of
Chemical Reactions
•EXCUSE- Energy Change
•Sometimes, Energy is absorbed by the
substances causing the temperature to
decrease. Example: Baking
Soda/Vinegar
•Sometimes , Energy is released by the
substances causing the temperature to
increase. Example: Magic Genie demo
Evidence of
Chemical Reactions
•COUGHS- Color Change
•This is evidence of a
chemical reaction only when
the other properties have also
changed. Example: Magic
Genie, Wood burning in
fireplace
Chemical
Change
Not a
Chemical
Change
Evidence of
Chemical Reactions
•BURPS- Bubbles (Gas release)
•When a gas is formed it may
try to escape causing bubbles.
The gas is a new substance.
Example: Baking Soda/Vinegar
Evidence of
Chemical Reactions
•SNEEZES- Sound & Smell
•Sometimes the only clue
you will have of a new
substance is a sound or
smell. Smell is the more
common of the two.
Example: Baking a cake, you
Elements
Compounds
Summary
• When you get to this slide, pause! Either go
back and review, or start working on your
Left Side for these notes! Near the end of
class, Mr. Huff will work with all of you to
come up with a summary.