Benchmark Review, Pure Substances and Mixtures

Benchmark Review

Pure Substances & Mixtures

​Classes of Matter

​All matter is classified as a Pure Substance OR a Mixture of substances.

• made up of 2 or MORE different substances PHYSICALLY combined.​

​Mixture (of substances)

• A substance that is chemically uniform throughout the substance.

• Made of IDENTICAL particles.

• can be an ELEMENT or a COMPOUND.

I

​Pure Substance

​Pure Substances -vs- Mixtures

Models of Matter: Elements

A model of an element will have all the same atoms.

(same color, same shape, etc.)

​or

Models of Matter: Compounds

A model of a compound will have identical particles, but each particle is made of more than one color.

​or

*Notice how the particles in both diagrams are made up of different colors, but all of the particles are identical to each other.

Models of Matter: Mixtures

A model of a mixtures will have at least one particle that is NOT identical to the others.

Mixture

of

Compounds

Mixture

of

Elements

Mixture

of

Elements and Compounds

Multiple Select

Which of the following diagrams represent an element?

Multiple Select

Choose the diagrams that represent a compound.

​More on Chemical Symbols

​Elements

​Compounds

• more than 1 uppercase letter

  • = more than 1 type of atom = COMPOUND

• Examples:

  • Iron Oxide - FeO

  • Sodium Chloride - NaCl

  • Water - H2O

• 1 uppercase =

  • 1 type of atom = ELEMENT

• Examples:

  • Iron - Fe

  • Oxygen - O

  • Hydrogen - H

  • Sodium - Na

Multiple Select

Which of the following substances are elements?

• Ag

• NaHCO₃

• KF

• H₂

Multiple Select

Choose all substances that are elements.

• Hydrogen

  ( H )

• Iron Oxide

  (Fe₂O₃)

• Baking Powder

• Silicon

  ( Si )

​More about Mixtures...

• The different substances in a mixture are PHYSICALLY combined.

​

• Because they are only PHYSICALLY combined, the different substances keep thier original properties.

• P​arts of a mixture can be separated by PHYSICAL means.

​

​

​

Multiple Select

Which of the following are true of Mixtures?

• made of identical particles

• parts physically combined

• can be homogenous or heterogeneous

• chemically uniform throughout

• Different parts are visible.

• uneven distribution of parts

• least mixed of all mixtures

• Easiest mixture to separate​

​Heterogeneous

• appears the same throughout.

• can NOT see different parts

• very well mixed

• MOST are Solutions (a substance dissolved in another)​

​Homogeneous

​Mixtures: Same or Different?

Mixtures are classified as Homogeneous or Heterogeneous.​

​Homogeneous

Examples​

​Heterogeneous

Examples​

Multiple Choice

Trail mix is a heterogenous mixture because __.

• it can be physically separated

• you can see the different parts

• the parts are edible

• it is made of more than 2 different substances

Multiple Choice

Which of the pictures represent a heterogenous mixture?

Multiple Choice

Which of the following mixtures is homogeneous?

• fruit salad

• milk

• chicken noodle soup

• chocolate chip cookie

Multiple Select

Which of the following are Pure Substances?

• compounds

• elements

• mixtures

Multiple Select

Which of the following substances are pure substances?

• Baking Soda

  (NaHCO₃ )

• Baking Powder

• steel

• Gold

  (Au)

Multiple Select

Which of the following substances are elements?

• Ag

• NaHCO₃

• KF

• H₂

Multiple Choice

Which of the following substances are compounds?

• O₂

• Cl₂

• Au

• HF

Multiple Choice

The air we breathe is made of many different gases, including Oxygen, Nitrogen, and trace amounts of Argon. The ratio of the gases may vary depending on location. Based on this information, what class of matter is air?

• a mixture

• a compound

• a pure substance

• an elemnet

Multiple Choice

Which of the following pure substances is an element?

• gold

• water

• sugar

• salt

Multiple Choice

Which of the following pure substances is a compound?

• Iron

• silver

• water

• gold

Multiple Select

Which of the following substances are mixtures?

• milk

• trail mix

• water

• gold

Multiple Select

Which of the following are pure substances?

• trail mix

• water

• gold

• milk

Multiple Choice

Which of the following models is a mixture of elements and compounds?

Multiple Select

Which of the following descriptions are true of a homogeneous mixture?

Choose all that apply.

• can be physically separated

• appears the same throughout

• physically combined

• has a chemical formula

Multiple Choice

You will need to know the more common compounds, even when the chemical formula is not included, so I have not included formulas for any of the choices.

Which of the following is a compound?

• iced tea

• water

• milk

• air

Match

Match the models with the correct description.

Mixture of Compounds

Mixture of Elements

Mixture of both Elements and Compounds

Element

Compound

• Mixture of Compounds

• Mixture of Elements

• Mixture of both Elements and Compounds

• Element

• Compound

Multiple Choice

Which of the following models represents an element?

Multiple Choice

Which of the following models represents a compound?

Multiple Select

Which of the following models are pure substances?

• Remember that a pure substance can be an element or a compound.

• Both pure substances and elements are compounds.

​

Pure Substance

• Diagram A is a compound, and Diagram B is an Element.

• So, BOTH are PURE SUBSTANCES!

A

B

Multiple Choice

Which of the following models represents a mixture compounds?