Question 1

Which of the following best describes a homogeneous mixture?

Accepted Answer

A mixture with uniform composition throughout, such as air.

Question 2

A sample of brass is analyzed in a laboratory. Which classification best fits brass?

Accepted Answer

Homogeneous mixture

Question 3

Which of the following is an example of a chemical property?

Accepted Answer

Flammability

Question 4

A student mixes iron filings and sulfur powder. The mixture is heated, and a black solid forms that cannot be separated by a magnet. What has occurred?

Accepted Answer

A compound has formed through a chemical change.

Question 5

Which of the following statements is TRUE regarding compounds?

Accepted Answer

Compounds are made of two or more elements chemically combined in fixed ratios.

Question 6

Which of the following is NOT a pure substance?

Accepted Answer

Air

Question 7

A glass of orange juice with pulp is best classified as:

Accepted Answer

Heterogeneous mixture

Question 8

Which of the following best explains why water (H2O) is considered a compound?

Accepted Answer

It can be separated into hydrogen and oxygen by chemical means.

Question 9

Which property would you use to separate a mixture of sand and salt?

Accepted Answer

Melting point

Question 10

A sample of matter has a definite volume but no definite shape. Which state of matter is this?

Accepted Answer

Liquid

Question 11

Which of the following is a correct statement about mixtures?

Accepted Answer

Each component in a mixture retains its own properties.

Question 12

A chemist is given a clear, colorless liquid. She evaporates the liquid and finds a white residue remains. What was the original sample?

Accepted Answer

A homogeneous mixture

Question 13

Which of the following is an example of a physical property that can be used to distinguish between two substances?

Accepted Answer

Melting point

Question 14

Which scenario best illustrates a chemical change?

Accepted Answer

Burning wood in a fireplace

Question 15

Which of the following is a heterogeneous mixture?

Accepted Answer

Granite

Question 16

A student claims that carbon dioxide (CO2) is a mixture because it contains more than one element. What is the flaw in this reasoning?

Accepted Answer

CO2 is a compound because its elements are chemically combined in fixed ratios.

Question 17

Which of the following best describes the difference between a compound and a mixture?

Accepted Answer

Compounds are chemically combined, mixtures are physically combined.

Question 18

Which of the following is an example of a pure substance that is NOT an element?

Accepted Answer

Sodium chloride (NaCl)

Question 19

A sample of matter expands to fill its container and can be compressed easily. Which state of matter does this describe?

Accepted Answer

Gas

Question 20

Which of the following best explains why air is classified as a homogeneous mixture?

Accepted Answer

Its composition is uniform throughout.

Classification of Matter: Key Definitions and Concepts

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