Chemistry Quiz

During a science experiment, Aria combined two elements in a test tube and a reaction occurred. What pure substance did she create?

• An element

• A compound

• A mixture

• A solution

Answer explanation

Aria combined two elements, resulting in a chemical reaction that formed a new substance. This new substance is a compound, as it consists of two or more elements chemically bonded together.

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NGSS.MS-PS1-2

Which of the following is an example of a mixture?

• Water

• Air

• Carbon dioxide

• Salt

Answer explanation

Air is a mixture of gases, primarily nitrogen and oxygen, along with other trace gases. In contrast, water, carbon dioxide, and salt are pure substances or compounds, not mixtures.

The samples represent models of pure substances and mixtures. Which of the models represents a heterogeneous mixture and why?

• Model 1 because it contains an even mixture of molecules.

• Model 2 because it only contains one type of molecule.

• Model 3 because it contains more than 1 type of molecule.

• Model 4 because it contains an uneven mixture of molecules.

Answer explanation

Model 4 represents a heterogeneous mixture because it contains an uneven mixture of molecules, indicating that different types of substances are not uniformly distributed.

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NGSS.MS-PS1-1

The graph shows the changes in temperature of a sample of benzene as its thermal energy is increased. At what point would you expect benzene to boil? (DOK 2)

• Point A

• Point B

• Point C

• Point D

Answer explanation

Benzene boils at its boiling point, which is typically indicated on the graph where the temperature stabilizes after increasing thermal energy. Point D represents this boiling point, as it shows the transition from liquid to gas.

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NGSS.MS-PS1-4

Which model illustrates the movement of particles as gas ionizes when thermal energy is added? (DOK 3)

• A

• B

• C

• D

Answer explanation

Model A effectively demonstrates how particles in a gas gain thermal energy, leading to increased movement and eventual ionization. This aligns with the concept of gas ionization under thermal energy.

Tags

NGSS.MS-PS1-4

While analyzing a mysterious material, which of the following could be considered its physical properties?

• Color, hardness, boiling point, and acidity.

• Color, hardness, boiling point, and electrical conductivity.

• Color, hardness, boiling point, and reaction with acid.

• Color, hardness, boiling point, and combustibility.

Answer explanation

The correct choice includes electrical conductivity, which is a physical property. Acidity and reaction with acid are chemical properties, while combustibility is also a chemical characteristic, not a physical one.

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NGSS.MS-PS3-4

Which of the following is a chemical reaction?

• milk turning sour

• ice melting into water

• water boiling into steam

• wood being cut into pieces

Answer explanation

Milk turning sour is a chemical reaction involving the fermentation of lactose by bacteria, resulting in the production of lactic acid. The other options are physical changes, not chemical reactions.

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NGSS.MS-PS1-2

Which of these is a chemical change that can occur to a sheet of paper?

• The paper can be torn.

• The paper can be soaked in water.

• The paper can turn yellow over time.

• The paper can be folded into a shape.

Answer explanation

The paper can turn yellow over time due to chemical changes like oxidation and degradation of lignin, which alters its composition. The other options involve physical changes, not chemical.

Which of the following processes involves a change in the state of matter?

• Boiling

• Rusting

• Burning

• Decomposing

Answer explanation

Boiling is the process where a liquid changes to a gas, indicating a change in the state of matter. Rusting, burning, and decomposing involve chemical changes but do not directly change the state of matter.

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NGSS.MS-PS1-4

Charlotte wants to experiment with sugar cubes. Which of the following causes a sugar cube to only change physically, not chemically?

• burning the sugar cube

• crushing the sugar cube and dissolving it in water

• reacting the sugar cube with acid

• chewing the sugar cube and digesting it

Answer explanation

Crushing the sugar cube and dissolving it in water only changes its physical state, as the sugar remains chemically the same. In contrast, burning, reacting with acid, and digestion involve chemical changes.

Tags

NGSS.MS-PS1-2