5-6 Review Exploring States of Matter

What is the shape of a solid?

• Fixed

• Variable

• Expanding

• Contracting

Answer explanation

The shape of a solid is fixed, meaning it maintains a definite shape and volume. Unlike liquids and gases, solids do not change shape easily, which is why 'Fixed' is the correct answer.

Which state of matter has a definite volume but no definite shape?

• Solid

• Liquid

• Gas

• Plasma

Answer explanation

A liquid has a definite volume, meaning it occupies a specific amount of space, but it does not have a definite shape, as it takes the shape of its container. This distinguishes it from solids, which have both definite shape and volume.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

What is a pure substance?

• A mixture of different elements

• A single type of element or compound

• A combination of solids and liquids

• A mixture of gases

Answer explanation

A pure substance consists of only one type of element or compound, meaning it has a uniform and definite composition. This distinguishes it from mixtures, which contain multiple substances.

Which of the following is a homogeneous mixture?

• Sand and water

• Oil and water

• Salt dissolved in water

• Iron filings and sulfur

Answer explanation

A homogeneous mixture has a uniform composition. Salt dissolved in water forms a solution where the salt is evenly distributed, making it homogeneous. In contrast, sand and water, oil and water, and iron filings and sulfur are not uniform mixtures.

Which element is a metal?

• Oxygen

• Carbon

• Iron

• Helium

Answer explanation

Iron is a metal, known for its strength and conductivity. In contrast, oxygen and helium are gases, while carbon is a non-metal. Therefore, the correct answer is Iron.

Identify a nonmetal from the periodic table.

• Sodium

• Chlorine

• Aluminum

• Copper

Answer explanation

Chlorine is a nonmetal found in Group 17 of the periodic table, known as the halogens. In contrast, sodium, aluminum, and copper are metals.

Which of the following has the highest density?

• Water

• Oil

• Iron

• Air

Answer explanation

Iron has the highest density among the options listed. Water is denser than oil, and both are significantly less dense than iron, which is a heavy metal. Air has the lowest density of all the choices.

What happens to the density of a substance when it is heated?

• Increases

• Decreases

• Stays the same

• Becomes zero

Answer explanation

When a substance is heated, its particles gain energy and move apart, leading to an increase in volume. Since density is mass divided by volume, an increase in volume results in a decrease in density.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Which of the following is evidence of a chemical change?

• Melting of ice

• Dissolving sugar in water

• Rusting of iron

• Boiling of water

Answer explanation

Rusting of iron is a chemical change because it involves a reaction with oxygen to form iron oxide, altering the substance's chemical composition. In contrast, melting ice, dissolving sugar, and boiling water are physical changes.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

What indicates the formation of a new substance?

• Change in shape

• Change in color

• Change in size

• Change in state

Answer explanation

A change in color often indicates a chemical reaction, leading to the formation of a new substance. Unlike changes in shape, size, or state, color change is a strong indicator of new chemical properties.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5