Pure Substances vs. Mixtures

Element

Compound

Homogeneous
mixture

Heterogeneous
mixture

1

2

1

2

• One type of atom
• Found on the periodic table
• One capital letter

Ne

C

H2

O2

Examples:

Visual Representation

How to Distinguish

​Elemental Molecule

• Two or more types of atom chemically

combined

• Two or more capital letters
• One substance with different elements

HBr

NH3

H2O NaHCO3

Examples:

Visual Representation

How to Distinguish

​Pure Substances

A pure substance is the same throughout (has uniform and definite composition).
A pure substance cannot be separated by physical means (ex: boiling or filtration)

Multiple Choice

Study the diagram. Which of the following is represented in the diagram?

• monoatomic element

• elemental molecules

• compound molecules

Multiple Choice

Study the diagram. Which of the following is represented in the diagram?

• monoatomic element

• elemental molecules

• compound molecules

Multiple Choice

Study the diagram. Which of the following is represented in the diagram?

• monoatomic element

• elemental molecules

• compound molecules

Multiple Choice

What is this?

• element

• compound

• mixture

Multiple Choice

What is this?

aluminum (Al)

• monoatomic element

• compound

• elemental molecule

Multiple Choice

All of the following are elemental molecules EXCEPT:

• carbon

  C₄

• nitrogen

  N₂

• oxygen

  O₃

• water

  H₂O

Multiple Choice

All of the following are compounds EXCEPT:

• hydrogen

  H

• sodium chloride

  NaCl

• water

  H₂O

• carbon dioxide

  CO₂

• Looks like one substance
• One phase
• Two or more substances
• “NaCl and H2O”

• Anything dissolved in H2O
• Salt Water
• Air (“O2 and N2 and CO2”)

Examples:

How to Distinguish

• Can see separation of

different substances

• Two or more phases

• Oil and Vinegar
• Granite
• Potting Soil

Examples:

How to Distinguish

​Mixtures

A mixture is not chemically bonded. That means each substance keeps its own identity and properties.
Because they don’t actually change into something new, mixtures can be separated by physical means.

Think of it like putting different colored LEGO bricks in one bucket. You can still pull out the red ones or the blue ones because they didn’t change into a new brick — they just got mixed together.

Multiple Choice

Chicken noodle soup is

• Homogeneous mixture

• Heterogeneous mixture

Multiple Choice

A bottle of dishwashing detergent contains a label on the back. The label has a long list of ingredients, including water, sodium lauryl sulfate, fragrance, and Blue dye #5.

What can you infer about the material in the bottle from this label and the appearance of the liquid?

• It is a heterogeneous mixture.

• It is a homogeneous mixture.

Element

Compound

Homogeneous
mixture

Heterogeneous
mixture

1

2

1

2

Multiple Choice

What is gold?

• Element

• Compound

• Homogenous mixture

• Heterogenous mixture

Multiple Choice

What is hot cocoa?

• Element

• Compound

• Homogenous Mixture

• Heterogenous mixture

Multiple Choice

What is carbon dioxide (CO₂)?

• Element

• Compound

• Homogenous Mixture

• Heterogenous Mixture

Multiple Choice

What is soda?

• Homogenous Mixture

• Heterogenous Mixture

• Element

• Compound

Multiple Choice

What is neon (Ne)?

• Element

• Compound

• Homogenous Mixture

• Heterogenous Mixture

Multiple Choice

What is pizza?

• Element

• Compound

• Homogenous Mixture

• Heterogenous Mixture

Multiple Choice

What is water (H₂O)?

• Element

• Compound

• Homogenous Mixture

• Heterogenous Mixture

​Exit Slip- Match It!

Match

Match the following models to their correct descriptions.

mixture of elements

mixture of elements and compounds

mixture of compounds

elements

compounds

• mixture of elements

• mixture of elements and compounds

• mixture of compounds

• elements

• compounds