Elements, Compounds, and Mixtures

What is a pure substance that consists of only one type of atom?

• Compound

• Element

• Mixture

• Solution

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

• Sand and water

• Oil and water

• Salt dissolved in water

• Iron filings and sulfur

• Element

• Compound

• Homogeneous mixture

• Heterogeneous mixture

Tags

NGSS.MS-PS1-1

Which of the following statements best describes a compound?

• A substance made of two or more elements chemically combined in a fixed ratio

• A mixture of different substances that can be physically separated

• A single type of atom

• A mixture of gases

Explain why air is considered a homogeneous mixture.

• It contains only one type of molecule.

• Its composition is uniform throughout.

• It can be separated by physical means.

• It is made of different elements chemically combined.

Which of the following is a characteristic of a heterogeneous mixture?

• Uniform composition throughout

• Components are not visibly distinguishable

• Components can be easily separated by physical means

• Consists of only one phase

Compare and contrast elements and compounds in terms of their composition and properties.

• Elements are made of one type of atom, while compounds are made of two or more types of atoms chemically combined.

• Elements and compounds both consist of multiple types of atoms.

• Compounds can be separated into elements by physical means.

• Elements have variable compositions, while compounds have fixed compositions.

Why is it important to distinguish between homogeneous and heterogeneous mixtures in scientific experiments?

• To ensure the correct chemical reactions occur

• To determine the exact number of atoms in a sample

• To predict the physical properties of the mixture

• To identify the elements present in the mixture

Which of the following best explains why compounds have different properties from the elements that form them?

• Compounds are mixtures of elements.

• The chemical bonds in compounds alter the properties of the elements.

• Compounds are made of a single type of atom.

• Elements lose their identity when mixed.

What is the main difference between a mixture and a compound?

• Mixtures are chemically combined, while compounds are not.

• Compounds have a fixed composition, while mixtures do not.

• Mixtures consist of a single element, while compounds consist of multiple elements.

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