ELEMENTS, COMPOUNDS & MIXTURES

Which statement identifies why oxygen is classified as a pure substance and air is classified as a mixture?

• Oxygen is more reactive than air.

• Oxygen has a higher density than air.

• Oxygen goes under a phase change, whereas air is always a gas.

• Oxygen contains only one substance, but air contains several substances.

Which of the following is an example of of a container filled with a pure substance rather than with a mixture?

• A tire filled with air.

• A jar filled with salt water.

• A balloon filled with helium.

• A glass filled with chocolate milk.

Which changes MUST happen for elements to become a compound?

• elements are heated

• a gas becomes a liquid

• elements dissolve in water

• chemical bonds form between atoms.

Tags

NGSS.MS-PS1-5

Water (H₂O), is not found on the periodic table because water is a...

• atom

• liquid

• mixture

• compound

Tags

NGSS.MS-PS1-1

Which of the following explains why saltwater is considered a mixture?

• It is composed of one element.

• It is composed of one compound.

• It is composed of two or more substances and has new chemical properties.

• It is composed of two or more substances and retains their own chemical properties.

Oxygen and iron combine chemically to form rust. Rust is classified as which of the following?

• an atom.

• an element.

• a compound.

• a mixture.

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

This image is a model of...

• an element

• a compound

• a homogenous mixture

• a heterogeneous mixture

Tags

NGSS.MS-PS1-1

This picture is a model of...

• an element

• a compound

• a homogenious mixture

• a heterogeneous mixture.

Tags

NGSS.MS-PS1-1

This picture is a model of a...

• element

• compound

• homogeneous mixture

• heterogeneous mixture

Tags

NGSS.MS-PS1-1

The image below is an example of

• an atom

• a molecule

• a homogeneous mixture

• a heterogeneous mixture

Tags

NGSS.MS-PS1-1