PURE SUBSTANCESVS.
MIXTURESPENTONEY 2017
WHAT IS A PURE SUBSTANCE?
Classification of matter that includes elements, molecules and
compounds
Cannot be separated by physical means such as distillation,
filtration, or sifting.
CHEMISTRY: MIXTURES AND PURE SUBSTANCES
Pure substance:
1. Element
2. Molecule
3. Compound
Not one of those? NOT A PURE SUBSTANCE!
CHEMISTRY: MIXTURES AND PURE SUBSTANCES
ELEMENT:
One or more of the same type of atom.
Ex: N N2
Both of these examples are called an element as we only have the element
Nitrogen (N) and nothing else.
CHEMISTRY: MIXTURES AND PURE SUBSTANCES
COMPOUND:
Two or more atoms chemically combined, at least one is
different.
Ex: CO2 (Carbon Dioxide) NaCl (salt)
Both of these examples are types of compounds.
CHEMISTRY: MIXTURES AND PURE SUBSTANCES
MOLECULE: 2 or more atoms chemically
combined.
Ex: N2 N3 H2O
CHEMISTRY: MIXTURES AND PURE SUBSTANCES
Ex: N2 N3
(These molecules are more specifically called an
“Element” because they are made up of only one type
of atom.)
*CHEMISTRY: MIXTURES AND PURE SUBSTANCES
Ex: H2O
(This is also a molecule, as it has 2 or more atoms
combined. But its more specific name is a compound. )
CHEMISTRY: MIXTURES AND PURE SUBSTANCES
The words “ELEMENT” and “COMPOUND” are specific types
of molecules.
ALL OF THE BOXES BELOW SHOW AN EXAMPLE OF A PURE SUBSTANCE
ELEMENT (C) ELEMENT (O2) COMPOUND (CO2)
CHEMISTRY: MIXTURES AND PURE SUBSTANCES
Examples of pure substances:
Salt (NaCl)
Sugar C6H12O6 (Glucose = Sugar)
H2O (Water)
ELEMENTS (like gold, silver, oxygen, nitrogen…any
on the periodic table)
CHEMISTRY: MIXTURES AND PURE SUBSTANCE
MIXTURE: two or more pure substances thrown
together. All substances keep their own identities.
*Example: When I mix sugar and water, I get the mixture sugar-water.
The sugar still has its own identity (it is sweet), the water still has its own
identity (its still water). Nothing new is created, and both can be
separated physically (boiling).
CHEMISTRY: MIXTURES AND PURE SUBSTANCE
There are two types of mixtures:
1. Homogenous
2. Heterogeneous
CHEMISTRY: MIXTURES AND PURE SUBSTANCE
Homogenous Mixture: Evenly mixed mixture
Examples:
Milk
Air (a mixture of gases you breath in)
Soda
Juice
WHAT IS A HOMOGENOUS MIXTURE?
• A mixture that is evenly distributed
• Commonly called solutions.
• Solution = Solute + Solvent
Solute: “stuff” being dissolved
Solvent: “stuff” doing the dissolving
• The solvent is present in greater quantity
• The solute is present in the lesser quantity
• Ex: Salt water: Salt = solute, Water = solvent
CHEMISTRY: MIXTURES AND PURE SUBSTANCE
Heterogeneous Mixture: Unevenly mixed mixture.
Example:
Salad
Legos
Cookie dough ice-cream
Chicken noodle soup
CHEMISTRY: MIXTURES AND PURE SUBSTANCE
ALL MIXTURES ARE PHYSICALLY COMBINED AND
CAN BE PHYSICALLY SEPARATED.
CHEMISTRY: MIXTURES AND PURE SUBSTANCE
Ways to physically separate a mixture:
• Boiling: evaporates liquid
• Sifting: Picking out pieces (like in cookies dough ice-cream =) )
• Filtering: Just like a pool filter, it takes out unwanted things.
*CHEMISTRY: MIXTURES AND PURE SUBSTANCE
What is the biggest differences between a mixture and a pure substance?
Mixtures Pure substance
Are physically mixed
together
Chemically combined
(bonded)
Can be physically
separated
Must be chemically
separated
(COPY CHART)
CLASSIFYING MATTER
Matter
Pure Substances Mixtures
Elements Compounds
Homogeneous Heterogeneous
Fe, OH2O, CO2
milk, tea Rocky Road ice
cream, muddy
waterMolecules
Fe2
(COPY CHART)
CHEMISTRY: MIXTURES AND PURE SUBSTANCE REVIEW
Question 1:
Which substance is not a compound?
a. Ne c. SiO2
b. HCN d. H2O2
CHEMISTRY: MIXTURES AND PURE SUBSTANCE REVIEW
Question 1:
Which substance is not a compound?
a. Ne c. SiO2
b. HCN d. H2O2
CHEMISTRY: MIXTURES AND PURE SUBSTANCE REVIEW
Question 2:
The components of a homogeneous mixture could be described as
a. inseparable c. chemically bonded
b. evenly mixed d. unevenly mixed
CHEMISTRY: MIXTURES AND PURE SUBSTANCE REVIEW
Question 2:
The components of a homogeneous mixture could be described as
a. inseparable c. chemically bonded
b. evenly mixed d. unevenly mixed
CHEMISTRY: MIXTURES AND PURE SUBSTANCE REVIEW
Question 3:
Iron filings are thrown into a pile of sand. What is the best way to
separate this mixture?
A. Use a magnet to pick up the sand.
B. Sift through the sand for all of the iron.
C. Use a magnet to pick up the iron filings.
CHEMISTRY: MIXTURES AND PURE SUBSTANCE REVIEW
Question 3:
Iron filings are thrown into a pile of sand. What is the best way to
separate this mixture?
A. Use a magnet to pick up the sand.
B. Sift through the sand for all of the iron.
C. Use a magnet to pick up the iron filings.
CHEMISTRY: MIXTURES AND PURE SUBSTANCE REVIEW
Question 4:
A substance contains two components joined by physical means. Which
best describes the substance?
A. element
B. compound
C. mixture
D. molecule
CHEMISTRY: MIXTURES AND PURE SUBSTANCE REVIEW
Question 4:
A substance contains two components joined by physical means. Which
best describes the substance?
A. element
B. compound
C. mixture
D. molecule
CHEMISTRY: MIXTURES AND PURE SUBSTANCE REVIEW
Question 5:
Which best describes water?
A. a compound
B. an element
C. a heterogeneous mixture
D. a homogeneous mixture
CHEMISTRY: MIXTURES AND PURE SUBSTANCE REVIEW
Question 5:
Which best describes water?
A. a compound
B. an element
C. a heterogeneous mixture
D. a homogeneous mixture
CHEMISTRY: MIXTURES AND PURE SUBSTANCE REVIEW
Question 6:
Which image below is a mixture?
A B C D
CHEMISTRY: MIXTURES AND PURE SUBSTANCE REVIEW
Question 6:
Which image below is a mixture?
A B C D
Element Compound molecule mixture of elements +
compounds