8 th grade science classifying matter: elements, compounds, and mixtures
TRANSCRIPT
8th Grade Science
Classifying Matter:Elements, Compounds, and
Mixtures
What is matter?Matter is….Anything that takes up space (volume) and has mass.
Water RocksAir WoodPlastic People
How is matter classified?
One way that scientists classify matter is by its composition (what it is made of) .
Ultimately, all matter can be classified as elements, compounds and mixtures
Elements and compounds are pure substances
Mixtures are not pure substance
What are Pure Substances?
What are Elements?Made of one type of atomCannot be separated into simpler substance by physical or chemical means.
Located on the periodic table
What are atoms?
The smallest part of an element
Atoms are the basic building blocks of all matter
Atoms chemically joined together are called moleculesmolecules
How are elements represented?
Elements have names and chemical symbols of either 1 or 2 letters
H He Hydrogen Helium
Some are natural and some are synthetic (man made)
Currently there are about 109 known elements
What are Compounds?
Are made of 2 or more atoms of different elements that are bonded together Made of elements in a specific ratio that is always the sameHas a chemical formulaCan only be separated by chemical means, not physically
What are Mixtures?A combination of two or more pure
substances that are not chemically combined.
substances held together by physical forces, not chemical
No chemical change takes place Has a random composition Each item retains its properties
in the mixture They can be separated physically
Chem4kids.com
Is it uniform throughout?Matter is also classified by its uniformityIf the answer is no, the matter is a
heterogeneous mixture.Considered the “least mixed.”Does not appear to be the same throughout.Particles are large enough to be seen and to
be separated from the mixture.
Is it uniform throughout?If the answer is yes, the matter is homogeneous (looks
the same throughout).If it can be physically separated it’s a homogeneous
mixture
If it can not be separated then it is a pure substance –element or compound
https://www.youtube.com/watch?v=3G472AA3SEs
https://www.youtube.com/watch?v=cnXV7Ph3WPk&list=PL96150D63D934C789
Mixtures vs. Compounds
http://www.bbc.co.uk/schools/ks3bitesize/science/chemistry/elements_com_mix_6.shtml
Can you identify the following?
You will be shown a series of photos. Tell if each photo represents an item composed of an element, compound, or mixture.
Review:An element contains just one type of atom. A compound contains two or more different
atoms joined together. A mixture contains two or more different
substances that are only physically joined together, not chemically.A mixture can contain both elements and
compounds.
Element, Compound, or Mixture?
Rocks
Element, Compound, or Mixture?
Rocks
Element, Compound, or Mixture?
Copper
Element, Compound, or Mixture?
Copper
Element, Compound, or Mixture?
Jelly Beans
Element, Compound, or Mixture?
Jelly Beans
Element, Compound, or Mixture?
Table Sugar
Element, Compound, or Mixture?
Table Sugar
Element, Compound, or Mixture?
Diamond
Element, Compound, or Mixture?
Diamond
Element, Compound, or Mixture?
Tea
Element, Compound, or Mixture?
Tea
Element, Compound, or Mixture?
Salt
Element, Compound, or Mixture?
Salt
Element, Compound, or Mixture?
Neon Gas
Element, Compound, or Mixture?
Neon Gas
Element, Compound, or Mixture?
Salad
Element, Compound, or Mixture?
Salad
Element, Compound, or Mixture?
Pure Water
Element, Compound, or Mixture?
Pure Water
Element, Compound, or Mixture?
Aluminum
Element, Compound, or Mixture?
Aluminum
Element, Compound, or Mixture?
Lemonade
Element, Compound, or Mixture?
Lemonade
Element, Compound, or Mixture?
Silver
Element, Compound, or Mixture?
Silver
Element, Compound, or Mixture?
Sand
Element, Compound, or Mixture?
Sand
