PURE SUBSTANCES VS. MIXTURES

I will know that an element is a pure substance

represented by a chemical symbol

Vocabulary

Pure Substance

Atom

Element

Molecule

Compound

Mixture

Heterogeneous

Homogeneous

Colloid

Solution

Suspension

I. Matter can be classified into 2 categories:

A. PURE SUBSTANCES

B. MIXTURES

A. Matter that contains only ONE (same) type of atom

compound, or molecule.

B. Pure substances include:

II. What is a PURE SUBSTANCE?

C. EXAMPLES:

III. ELEMENTS

A. An ELEMENT is a pure substance that

contains only 1 type of atom.

B. 118 different elements exist on Earth

C. Located on the Periodic Table

D. Examples:

1. Silver 2. Helium 3. Sulfur

More Elements….

carbon bromine chlorine mercury

silicon copper uranium krypton

D. Elements are organized on the PERIODIC TABLE

IV. WHAT ARE COMPOUNDS ?

A. PURE SUBSTANCES composed of 2 or more DIFFERENT elements

joined by chemical BONDS.

B. Elements are CHEMICALLY COMBINED!

C. Can only be separated through a CHEMICAL CHANGE.

D. Have CHEMICAL FORMULAS. Ex. NaCl=sodium chloride (AKA Salt)

E. The properties of a compound are DIFFERENT from the elements

that make up the compound.

.

Video clip: Sodium reaction with water

Common Compounds…

water (H2O) salt (NaCl sodium chloride) ammonia (NH3)

rust (Fe2O3 iron oxide) caffeine (C8H10N4O2) sugar (C6H12O6)

1. When you add sugar to coffee, tea, or

lemonade, the sugar disappears.

What do you think happens to the sugar?

2. What happens if you don’t like one of the

ingredients that is on a pizza, or in a salad,

or in a party mix?

THINK about the following:

Mixtures can be physically separated!

V. WHAT ARE MIXTURES?

A. 2 or more substances that are PHYSICALLY combined.

B. Substances retain their identity (don’t change their composition)

Example: Chocolate milk

C. Mixtures are NOT pure substances!

D. They can be separated by PHYSICAL means.

E. Examples:

Once combined the milk is

still milk and the chocolate

is still chocolate!

Blood Soil SaltwaterClip: Mixtures

VI. Types of Mixtures

A. HOMOGENEOUS MIXTURES:

1. “Homo”-prefix meaning “same”

2. Substances are spread evenly throughout

3. You CAN NOT see the individual substances

4. Examples:

Kool-Aid air brass

steel milk

B. Heterogeneous Mixtures

1. “hetero” means different

2. The individual parts CAN BE SEEN!

3. Examples:

a. soil

b. trail mix

c. cheeseburger

d. pepperoni pizza

PRACTICE: Identify each of the following as either

heterogeneous or homogeneous:

1. soft drinks

2. ocean water

3. Italian salad dressing

4. vegetable soup

5. concrete

6. Snickers bar

7. blood

8. oil & water

9. dirt

10. marshmallow

COMPOUNDS MIXTURES

1.CANNOT be physically

separated

1. Can be physically separated

2. Substances are chemically

combined

2. Substances are physically

combined

3. Requires a CHEMICAL

change to occur

3. Requires a PHYSICAL

change to occur

4. Have different properties

from the elements it contains.

4. Substances maintain their

original identity

5. Always have a fixed ratio of

elements

5. Ratio of substances can vary

6. Heat is either absorbed or

produced when a compound

forms

6. Making mixtures does not

produce or require heat

VII. Differences between compounds &

mixtures

A Differences

Comparing Compounds & Mixtures: Double Bubble Map

B Differences

B Differences

B Differences

COMPOUNDS

A Differences

A Differences

MIXTURES

AB Similarit ies

ABSimilarit ies

ABSimilarit ies