Classifying Matter: Mastery Test

Select the correct answer. Chemists investigated an unknown substance and found it to have the following characteristics: - Different components could be observed in the substance. - Different samples of the substance appeared to have different proportions of the components. - The components could be easily separated using filters and sorting. Which statement most accurately describes this substance?

• The substance is a compound.

• The substance is an element.

• The substance is a heterogeneous mixture.

• The substance is a homogeneous mixture.

Answer explanation

The substance is a heterogeneous mixture because it has visibly different components, varying proportions, and can be easily separated, indicating it is not uniform throughout.

What is the term for a mixture that has a uniform composition throughout?

• Heterogeneous mixture

• Homogeneous mixture

• Solution

• Suspension

Answer explanation

A homogeneous mixture has a uniform composition throughout, meaning its components are evenly distributed. In contrast, a heterogeneous mixture has distinct, separate parts. A solution is a type of homogeneous mixture.

When Phillip analyzed an unknown substance X, he found that it contained only one kind of atom. Phillip was unable to convert the substance to a simpler one. What is substance X?

• a compound

• an element

• a heterogeneous mixture

• a homogeneous mixture

Answer explanation

Substance X contains only one kind of atom and cannot be simplified further, indicating it is an element. Compounds consist of two or more types of atoms, while mixtures contain multiple substances, making 'an element' the correct choice.

Which of the following are considered pure substances?

• element

• compound

• homogeneous mixture

• heterogeneous mixture

Answer explanation

Pure substances consist of only one type of particle. Elements are pure substances made of one kind of atom, while compounds are made of two or more elements chemically combined. Homogeneous and heterogeneous mixtures contain multiple substances.

Which state of matter is highly compressible, is made of particles moving independently of each other, and is present in large quantities near Earth's surface?

• solid

• liquid

• gas

• plasma

Answer explanation

Gas is highly compressible, with particles that move independently, allowing it to fill large volumes. This state of matter is abundant near Earth's surface, making it the correct answer.

Which of the following describes a compound? (Hint: Carbon and oxygen both appear on the periodic table.)

• a piece of pure carbon, containing only carbon atoms

• oxygen gas surrounding a solid piece of carbon

• a substance made of two oxygen atoms for each carbon atom

• carbon and oxygen atoms mixed without being bonded together

Answer explanation

A compound is a substance formed when two or more elements are chemically bonded. The correct choice describes a compound made of two oxygen atoms for each carbon atom, indicating a specific ratio and bonding.