Classifying Matter Essentials

Carbon is considered an element, while carbon dioxide is considered a compound. This is because carbon dioxide is–

• given off by green plants.

• a gas at room temperature.

• useful to human beings.

• made of two different elements.

Which of the following is composed of two or more different substances (each of which retains its own individual properties) that are physically combined?

• Element

• Mixture

• Atom

• Molecule

H2O is a compound. The compound H2O can only be broken down into H and O by–

• chemical changes.

• size changes.

• temperature changes.

• physical changes.

The smallest particle of any particular type of matter is known by which of the following terms?

• Atom

• Element

• Chemical

• Compound

A pure substance that cannot be broken down into a simpler substance is known by what term?

• Molecule

• Element

• Compound

• Crystal

When elements combine to form a compound, it is reasonable to predict that the compound–

• will have a greater total volume than the elements.

• will have less mass than the elements.

• will have the same characteristics as the elements.

• will have physical properties different from the elements.

In the following illustrations, different colors represent different kinds of atoms. Which one correctly labels an element, a compound, and a mixture?

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• 
• 
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Two samples are poured through filters. Sample #1 is separated into two substances by the filtration, while Sample #2 remains unchanged by filtration. Which of the following is the most reasonable conclusion based on these observations?

• It can only be concluded that Sample #1 is a mixture, but more testing is necessary to classify Sample #2.

• It can only be concluded that Sample #1 is a compound, but more testing is necessary to classify Sample #2.

• It can be concluded that Sample #1 is a compound and that Sample #2 is a mixture.

• It can be concluded that Sample #1 is a mixture and that Sample #2 is a compound.

Which of the following is the best description of an element?

• A naturally occurring mineral made of more than one substance.

• A substance that cannot be broken down into simpler substances.

• A small particle of a substance with properties that change when heated.

• A collection of atoms that have different abilities when joined together.

How are elements and compounds different?

• Compounds are represented by chemical symbols of one letter, elements by two.

• There are an infinite number of elements, but a limited number of compounds.

• Elements are always larger units of matter, and compounds are smaller.

• A compound is a combination of two or more types of matter, an element is one type.