Which of the following best describes an open system in the context of the classification of matter?

Which of the following is a mixture?

Almost everything around us is made of chemicals. If something is not made of chemicals, what is it most likely considered?

Which of the following is good evidence that an unknown sample is a pure substance?

Everything you can touch and everything you can see is matter except for which of the following?

Which statement best describes the components of a mixture?

Which of the following best describes a heterogeneous mixture?

Which of the following samples is a pure substance?