Upload
dokhue
View
216
Download
0
Embed Size (px)
Citation preview
How could you sort these and classify them?:
A bin of markers?
A deck of cards?
A lot filled with new cars?
HOW WOULD YOU CLASSIFY THESE TYPES OF MATTER?
How Do We Classify Matter in Science?????
Scientists like to classify things.
It wouldn’t help too much to just classify matter based on their color or smell….
One way that scientists classify matter is by its composition (what it is made of).
Ultimately, all matter can be classified as Mixtures or Pure Substances.
Classifying MATTER- we must
start by knowing that …….
The building blocks of all matter
are elements (like on the periodic
table)
Atoms are the smallest unit of
an element that maintains the
properties of that element
For example,
one atom of gold (Au) is
still gold, but if you
broke the atom into
smaller pieces,
it wouldn’t be gold
Pure Substances
An Element is a pure substances
made of only one type of atom
For example,
O2 C Ca He
7
Pure Substances
Compounds
A compound is a substance that
is made from the atoms of two
or more elements that are
chemically combined.
Examples: NaCl (salt)
H2O (water)
Classification of Matter
by Composition
All matter can be classified into two
categories: Pure Substances or
Mixtures
9
Classification of Matter
by Composition
A pure substance is a single
substance with fixed composition
and constant properties
Gold, Calcium, Hydrogen, Sugar
Salt, Calcium Carbonate
10
Classifying Pure Substances
Mixtures
Homogeneous
(Solutions)
Heterogeneous
SuspensionColloid
PURE
SUBSTANCE
COMPOUND ELEMENT
Pure Substances
An Element is a pure substances
made of only one type of atom
For example,
O2 C Ca He
12
Pure Substances
Compounds
A compound is a substance that
is made from the atoms of two
or more elements that are
chemically combined.
Examples: NaCl (salt)
H2O (water)
Classification of Mixtures
homogeneous = mixture that has
uniform composition throughout
AKA: Solution
Every piece of a sample has identical
characteristics, though another sample
with the same components may have
different characteristics.
atoms or molecules mixed uniformly
15
Homogeneous Mixtures
(Solutions) • Solutions
– Appear Uniform
– Mixed particles are dissolved and so small that they don’t reflect light (scattering).
– Nothing settles out over time.
– Nothing filters out.
– Can be in solid, liquid, or gas form!
Classification of Mixtures
heterogeneous = mixture that does not
have uniform composition throughout–
you can see the different parts
contains regions within the sample with
different characteristics
atoms or molecules not mixed uniformly
19
Heterogeneous mixtures You can see the particles that make
it up.
Sand and pebbles
Oil and water
Cereal
Heterogeneous Mixtures – 2 types Heterogeneous
• Colloids
– Looks uniform but particles aren’t really dissolved. Particles are still large enough to scatter light. Looks cloudy when light goes through it.
• Suspensions – Don’t look uniform,
filters, settles out over time, and particles scatter light.
Heterogeneous Mixtures – 2 types Heterogeneous or solution (homogeneous)?
• How can we tell if a mixture is truly homogeneous or heterogeneous?
• SHINE A LIGHT THROUGH IT AND YOU WILL KNOW!
Tyndall Effect This is the scattering
of light reflecting off
little particles.
Solution: cannot see
beam of light
Heterogeneous: you
can see beam of light
(reflecting off litte
particles)
Density
Density –
More dense objects will sink when
compared to less dense objects.
What do you think has the highest
density?
WATER, OIL, MOLASSES?
Good Morning!! For your warmup, please
use your notes to figure out
the matching section of the
handout (back of sheet)
Also, if you have any
pennies with you, please
donate during the class….
Density
Density – How much
matter is contained in
a certain volume
D=mass/volume
What is more dense,
a cup of unpopped
popcorn kernels or a
cup of popped
popcorn?