States of Matter and Elements vs Compounds vs Mixtures

Which of the following is an example of the formation of a mixture?

• Rust forming on an iron nail.

• Sugar crystals dissolving in water.

• Sodium and chlorine forming table salt.

• Hydrogen and oxygen reacting to produce oxygen.

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 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.

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

• atom

• liquid

• mixture

• compound

Tags

NGSS.MS-PS1-1

A student finds a beaker containing a substance in the lab. The student filters the contents of the beaker and notices that a solid is left on the filter paper. What can the student conclude about the type of matter of the original matter?

• The original material was a mixture.

• The original material was a compound.

• The original material was either an element or a compound.

• The original material was either a mixture or a compound.

Tags

NGSS.MS-PS1-2

A student is given a sample of an unknown substance. They observe that the substance has a uniform appearance and cannot be separated into different components by physical means. What can the student conclude about the substance?

• It is a heterogeneous mixture.

• It is a homogeneous mixture.

• It is a compound.

• It is an element.

A pure substance that contains more than one type of atom chemically bonded together is a(n) (a)   .

• Element

• Compound

• Mixture

Which of the following best describes a compound?

• A mixture of two or more elements that can be separated by physical means.

• A pure substance composed of two or more elements chemically combined in a fixed ratio.

• A substance that cannot be broken down into simpler substances.

• A homogeneous mixture of substances.

What is the main difference between a pure substance and a mixture?

• Pure substances have variable compositions, while mixtures have fixed compositions.

• Pure substances can be separated by physical means, while mixtures cannot.

• Pure substances have a fixed composition, while mixtures have variable compositions.

• Pure substances are always elements, while mixtures are always compounds.

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