Understanding Matter: Pure Substances and Mixtures

What defines a pure substance in terms of its composition?

• It can be separated by physical processes.

• It is always a mixture of compounds.

• It contains only one type of matter.

• It contains multiple types of elements.

Which of the following is an example of a pure substance?

• Water

• Steel

• Salted water

• Air

How can the components of a mixture be separated?

• By chemical reactions

• By physical processes

• By changing their chemical composition

• By adding more substances

Which of the following is a homogeneous mixture?

• A mixture of sand and iron filings

• Air

• Sedimentary rock

• Oil and water

What is a characteristic of a heterogeneous mixture?

• It cannot be separated by physical means.

• It contains only one type of element.

• It has a uniform composition throughout.

• Its components are not evenly distributed.