Test PREP (Chemistry intro)

Mixtures are different than pure substances because mixtures-

• have lower boiling points

• can be separated physically

• are less dense than pure substances

• contain only one type of atom

Answer explanation

Mixtures can be separated physically, unlike pure substances which cannot be separated by physical means.

What happens when a material sublimes? “It goes from …”

• A solid to a gas

• A gas to a plasma

• A gas to a solid

• A gas to a liquid

Answer explanation

When a material sublimes, it goes from a solid directly to a gas phase without passing through the liquid phase.

Which of the following would be considered a Heterogeneous mixture?

• Trail Mix

• Oxygen

• Air

• Pure, Distilled Water

Answer explanation

Trail Mix is considered a Heterogeneous mixture because it contains different components that are visibly distinguishable, such as nuts, seeds, and dried fruits.

Any material consisting of only one type of atom is classified as what?

• A compound

• An element

• A heterogeneous mixture

• A homogeneous mixture

Answer explanation

Any material consisting of only one type of atom is classified as an element, as elements are made up of only one type of atom.

When different atoms combine _______ are formed.

• compounds

• elements

• heterogeneous mixtures

• homogeneous mixtures

Answer explanation

When different atoms combine, compounds are formed. Compounds are substances composed of two or more different elements chemically bonded together.

A compound is represented by its _______.

• atomic number

• chemical number

• chemical formula

• number of atoms

Answer explanation

A compound is represented by its chemical formula, which shows the types and numbers of atoms present in the compound.

Which classification of matter is a pure substance?

• Elements

• Elements and compounds

• Compounds

• Elements and mixtures

• Mixtures

Answer explanation

A pure substance can be either an element or a compound, making the correct classification 'Elements and compounds'.

The amount of matter (mass) in a certain amount of space (volume) is known as the object's ______________ .

• density

• mass

• matter

• volume

Answer explanation

Density is the amount of matter (mass) in a certain amount of space (volume), making it the correct term for the given question.

At a school carnival, Claire watched a clown fill balloons from a metal tank of helium gas. She never knew that helium balloons could be filled from a tank like this. She had no clue that gasses could be held in a tank, she’s only seen gases in balloons. Which property of the helium gas changes as it moves into the balloons?

• Color

• Mass

• Smell

• Volume

Answer explanation

The property of the helium gas that changes as it moves into the balloons is its Volume. The gas expands to fill the balloon, increasing its volume.

In which region(s) does temperature remain constant?

• Region 1, 3, & 5

• Region 2 & 4

• Region 1 only

• Region 1 & 2

Answer explanation

Regions 2 and 4 have constant temperature as there is no change in temperature within these regions.