Question

chapter 2 properties of matter
section 2.1 classifying matter (pages 38 - 44)
this section explains how materials are classified as pure substances or mixtures. it discusses types of pure substances and mixtures.
reading strategy (page 38)
summarizing as you read, complete the classification of matter in the diagram below. for more information on this reading strategy, see the reading and study skills in the skills and reference handbook at the end of your textbook.
matter
mixture
element
pure substances (page 39)

1. is the following sentence true or false? every sample of a pure substance has exactly the same composition and the same properties.
2. what are the two categories of pure substances?

a.
b.
elements (pages 39 - 40)

1. what is an element?
2. is the following sentence true or false? the smallest particle of an element is an atom.
3. why does an element have a fixed, uniform composition?
4. circle the letter before each element that is a gas at room temperature.

a. carbon
b. oxygen
c. mercury
d. nitrogen
match each element to its correct symbol.
element symbol

1. aluminum a. c
2. gold b. al
3. carbon c. au

Explanation:

1. By definition, pure substances have a consistent composition and properties throughout all samples.
2. Pure substances are categorized into elements and compounds.
3. An element is a substance that cannot be broken down into simpler substances by chemical means.
4. The smallest particle of an element that retains its properties is an atom.
5. An element has a fixed, uniform composition because it consists of only one type of atom.
6. Oxygen and nitrogen are gases at room - temperature. Carbon is a solid and mercury is a liquid at room - temperature.

7 - 9. The chemical symbol for aluminum is Al, for gold is Au, and for carbon is C.

Answer:

1. True
2. a. Element

b. Compound

1. A substance that cannot be broken down into simpler substances by chemical means.
2. True
3. Because it consists of only one type of atom.
4. b. oxygen, d. nitrogen
5. b. Al
6. c. Au
7. a. C